The role of cytoskeleton in cell changes under condition of simulated microgravity

Single cells and cell culture are very good model for estimation of primary effects of gravitational changes. It is suggested that cell cytoskeleton plays a key role in mechanisms of adaptation to mechanical influences including gravitational ones. Our results demonstrated that cultured cells of human vascular endothelium (correction of endotheliun) are highly sensitive to hypogravity (clinorotation) and respond by significant decrease of cell proliferative activity. Simultaneously it was noted that the formation of confluent monolayer appeared early in cultures exposed to simulated microgravity due to accelerated cells spreading. Long-term hypogravity (several hours or days) leads to significant changes of cell cytoskeleton revealed as microfilament thinning and their redistribution within cell. Such changes were observed only in monolayer cells and not in cell suspensions. Gravitational forces as known to be modificators of cell adhesive ability and determine their mobility. Hypogravity environment stimulated endothelial cell migration in culture: 24-48 hrs pre-exposition to hypogravity significantly increased endothelial cell migration resulting in 2-3-fold acceleration of mechanically injured monolayer repair. Obtained results suggest that the effects of hypogravity on cultured human endothelial cells are, possibly, associated with protein kinase C and/or adenylate cyclase activity and are accompanied by noticeable functional cell changes.     

Women's health issues and space-based medical technologies

Biotechnological advances from NASA-sponsored research are reviewed with an emphasis on their effects on women's health issues. The Rotating-Wall Vessel (RWV) has allowed scientists to generate three-dimensional cellular growth. The RWV has been used to study the growth and spread of breast and ovarian tumor cells. Further applications include the study of biological and chemotherapeutic agents, gene expression, and genetic studies of cancer cells. The RWV also is used to study other cancers, cartilage cell growth, and immunotherapy for tumor cells. Other biomedical research related to women's health includes study of bone loss, immune changes, crystal structure and growth, and the effects of long-term radiation exposure on the endometrium.     

T-cell immunity and cytokine production in cosmonauts after long-duration space flights

Long-duration spaceflight effects on T-cell immunity and cytokine production were studied in 12 Russian cosmonauts flown onto the International Space Station. Specific assays were performed before launch and after landing and included analysis of peripheral leukocyte distribution, analysis of T-cell phenotype, expression of activation markers, apoptosis, proliferation of T cells in response to a mitogen, concentrations of cytokines in supernatants of cell cultures. Statistically significant increase was observed in leukocytes’, lymphocytes’, monocytes’ and granulocytes’ total number, increase in percentage and absolutely number of CD3⁺CD4⁺-cells, CD4⁺CD45RA⁺-cells and CD4⁺CD45RA⁺/CD4⁺CD45RО⁺ ratio, CD4⁺CD25^+Bright regulatory cells (p<0,05) in peripheral blood after landing. T-lymphocytes’ capacity to present CD69 and CD25 on its own surfaces was increased for the majority of crewmembers. Analysis of T-cell response to PHA-stimulation in vitro revealed there were some trends toward reduced proliferation of stimulated T-lymphocytes. There was an apparent post flight decrease in secreted IFN-g for the majority of crewmembers and in most instances there was elevation in secreted IL-10. It revealed depression of IFN-g/IL-10 ratio after flight. Correlation analysis according to Spearman’s rank correlation test established significant positive correlations (p<0.05) between cytokine production and T-cell activation (CD25+, CD38+) and negative correlation (p<0.05) between cytokine production and number of bulk memory CD4+T-cells (CD45RO+). Thus, these results suggest that T-cell dysfunction can be conditioned by cytokine dysbalance and could lead to development of disease after long-duration space flights.     

T cell regulation in microgravity – The current knowledge from in vitro experiments conducted in space,parabolic flights and ground-based facilities

Dating back to the Apollo and Skylab missions, it has been reported that astronauts suffered from bacterial and viral infections during space flight or after returning to Earth. Blood analyses revealed strongly reduced capability of human lymphocytes to become active upon mitogenic stimulation. Since then, a large number of in vitro studies on human immune cells have been conducted in space, in parabolic flights, and in ground-based facilities. It became obvious that microgravity affects cell morphology and important cellular functions. Observed changes include cell proliferation, the cytoskeleton, signal transduction and gene expression. This review gives an overview of the current knowledge of T cell regulation under altered gravity conditions obtained by in vitro studies with special emphasis on the cell culture conditions used. We propose that future in vitro experiments should follow rigorous standardized cell culture conditions, which allows better comparison of the results obtained in different flight- and ground-based experiment platforms.     

Can ultrasound counteract bone loss? Effect of low-intensity ultrasound stimulation on a model of osteoclastic precursor

The aim of the present work is to determine whether mechanical stress caused by ultrasound (US) exposure affects osteoclastic precursor cells, thus addressing the hypothesis that mechanical strain-induced perturbation of preosteoclastic cell machinery can contribute to the occurrence of bone turnover alterations. Moreover, cell cytoskeleton was studied because of its supposed involvement in cell mechanotransduction.Our experimental model was the FLG 29.1 human cell line, previously characterized as an osteoclastic precursor model. Cell proliferation was quantified by trypan blue exclusion assay. Cell morpho-functional state was monitored by multispectral imaging autofluorescence microscopy. The expression of cytoskeletal components and markers of proliferation (Ki67) and osteoclastic differentiation (RANK) was analysed by immunocytochemistry.The findings demonstrated that US stimulation affects FLG 29.1 cell growth, depresses the expression of cytoskeletal components and markers of proliferation and differentiation, induces cell damage, thus supporting the hypothesis that US exposure inhibits osteoclastogenesis.These results have been compared with those obtained previously by exposure of FLG 29.1 cells to modelled hypogravity conditions. Finally, the possibility to utilize US stimulation for counteracting osteoporosis has been discussed.     

看红色文化如何与动漫经济相结合——动画电影《西柏坡》简评

时下红色文化热,唱红歌活动大江南北如火如荼。红色电影《西柏坡》将红色文化教育、红色旅游经济与动漫传播相结合,是一次用动画形式弘扬红色文化的大胆尝试。     

Cell-to-cell interactions in changed gravity: ground-based and flight experiments

Cell-to-cell interactions play an important role in all physiological processes and are mediated by humoral and mechanical factors. Mechanosensitive cells (e.g., osteocytes, chondrocytes, and fibroblasts) can be studied ex vivo to understand the effects of an altered gravity environment. In particular, cultured endothelial cells (EC) are very sensitive to a broad spectrum of mechanical and biochemical stimuli. Earlier, we demonstrated that clinorotation leads to cytoskeletal remodeling in cultured ECs. Long-term gravity vector changes also modulate the expression of surface adhesion molecules (ICAM-1, E-selectin, VCAM-1) on cultured ECs. To study the interactions of geterological cells, we cocultured endothelial monolayers and human lymphocytes, immune cells and myeloleucemic (K-560) cells. It was found that, although clinorotation did not alter the basal adhesion level of non-activated immune cells on endothelial monolayers, the adhesion of PMA-activated lymphocytes was increased. During flight experiments onboard the Russian segment of the International Space Station, we measured the cytotoxic activity of natural killer (NK) cells incubated with labeled target cells. It was found that immune cells in microgravity retained their ability to contact, recognize, and destroy oncogenic cells in vitro. Together, our data concerning the effects of simulated and real microgravity suggest that, despite changes in the cytoskeleton, cell motility, and expression of adhesion molecules, cell-cell interactions are not compromised, thus preserving the critical physiological functions of immune and endothelial cells.     

看红色文化如何与动漫经济相结合——动画电影《西柏坡》简评

时下红色文化热,唱红歌活动大江南北如火如荼。红色电影《西柏坡》将红色文化教育、红色旅游经济与动漫传播相结合,是一次用动画形式弘扬红色文化的大胆尝试。     

Thyrotropin receptor and membrane interactions in FRTL-5 thyroid cell strain in microgravity

The aim of this work was to analyze the possible alteration of thyrotropin (TSH) receptors in microgravity, which could explain the absence of thyroid cell proliferation in the space environment. Several forms of the TSH receptor are localized on the plasma membrane associated with caveolae and lipid rafts. The TSH regulates the fluidity of the cell membrane and the presence of its receptors in microdomains that are rich in sphingomyelin and cholesterol. TSH also stimulates cyclic adenosine monophosphate (cAMP) accumulation and cell proliferation. Reported here are the results of an experiment in which the FRTL-5 thyroid cell line was exposed to microgravity during the Texus-44 mission (launched February 7, 2008, from Kiruna, Sweden). When the parabolic flight brought the sounding rocket to an altitude of 264?km, the culture media were injected with or without TSH in the different samples, and weightlessness prevailed on board for 6 minutes and 19 seconds. Control experiments were performed, in parallel, in an onboard 1g centrifuge and on the ground in Kiruna laboratory. Cell morphology and function were analyzed. Results show that in microgravity conditions the cells do not respond to TSH treatment and present an irregular shape with condensed chromatin, a modification of the cell membrane with shedding of the TSH receptor in the culture medium, and an increase of sphingomyelin-synthase and Bax proteins. It is possible that real microgravity induces a rearrangement of specific sections of the cell membrane, which act as platforms for molecular receptors, thus influencing thyroid cell function in astronauts during space missions.     

基于龙凤文化背景下的廊坊市公共设施景观规划研究

城市公共设施是城市环境的重要组成部分，也是城市时代精神和文化状态的标准。廊坊市的公共设施景观规划应“以人为本”，有效地结合廊坊“龙凤文化”的历史文化传承，从中体现出高尚的城市品质、精致生活环境、优雅的生活情趣。     

Space education, a tool to influence the cultural development in the society

Culture is an organized group of learned responses of a particular society, or the total round of human activities, not due to heredity, shared by members of a group. This means that culture is a dynamic process and it is in tight relationship to the civilization as a tool to master their all day's tasks. Space science is a result of the shift from the mass production civilization to the knowledge civilization. The science had opened new ways of thinking into a new environment, space. The ability to develop thinking to new living areas is already a learned response to the environment and therefore an act of culture.

The next changes in culture are a result of the different view, mankind has from earth looking back out of the spacecraft window. We see now with other eyes the small and vulnerable living area of mankind. We see no political limits partitioning the surface. We understand time zones as systems properties of the regions. This has up to now influenced big groups of the societies. As this view has to be shared by all members of the societies in the same mode, space education has to organize this effect.     

Spaceflight and clinorotation cause cytoskeleton and mitochondria changes and increases in apoptosis in cultured cells.

The cytoskeleton is a complex network of fibers that is sensitive to environmental factors including microgravity and altered gravitational forces. Cellular functions such as transport of cell organelles depend on cytoskeletal integrity; regulation of cytoskeletal activity plays a role in cell maintenance, cell division, and apoptosis. Here we report cytoskeletal and mitochondria alterations in cultured human lymphocyte (Jurkat) cells after exposure to spaceflight and in insect cells of Drosophila melanogaster (Schneider S-1) after exposure to conditions created by clinostat rotation. Jurkat cells were flown on the space shuttle in Biorack cassettes while Schneider S-1 cells were exposed to altered gravity forces as produced by clinostat rotation. The effects of both treatments were similar in the different cell types. Fifty percent of cells displayed effects on the microtubule network in both cell lines. Under these experimental conditions mitochondria clustering and morphological alterations of mitochondrial cristae was observed to various degrees after 4 and 48 hours of culture. Jurkat cells underwent cell divisions during exposure to spaceflight but a large number of apoptotic cells was also observed. Similar results were obtained in Schneider S-1 cells cultured under clinostat rotation. Both cell lines displayed mitochondria abnormalities and mitochondria clustering toward one side of the cells which is interpreted to be the result of microtubule disruption and failure of mitochondria transport along microtubules. The number of mitochondria was increased in cells exposed to altered gravity while cristae morphology was severely affected indicating altered mitochondria function. These results show that spaceflight as well as altered gravity produced by clinostat rotation affects microtubule and mitochondria organization and results in increases in apoptosis. Grant numbers: NAG 10-0224, NAG2-985.     

Economic value analysis of the return from the Korean astronaut program and the science culture diffusion activity in Korea

In this study, we analyze the economic effects from the Korean Astronaut Program (KAP) and the subsequent Science Culture Diffusion Activity (SCDA). Korea has had a huge practical effect on the development of science and technology and has increased international awareness of Korea by producing Korea's first astronaut. There has also been a large, ripple effect on space related industries. In addition, the KAP has exercised a far-reaching influence on Korean society and culture by boosting all science and engineering and inspiring national pride. After the KAP, astronauts' outreach activities, such as lectures for the general public; interviews on television, newspapers and magazines; participating in children's science camps; and distributing publications and DVDs about astronaut program for general public, were instituted for diffusing science culture. Thus, positive effects such as the promotion of Korea's level of technology, student interest in science and engineering fields, and the expansion of the industrial base were reinforced after the KAP. This study is aimed at evaluating the economic significance and the value of return through analyzing the effects of the KAP and the subsequent Science Culture Diffusion Activity.     

Characterization of a novel miniature cell culture device

Recent advancements in the field of microfluidics have generated much interest in the advent of a miniaturized cell culture device. In this study, we developed a novel miniature culture system for the continuous long-term cultivation of both anchorage dependent and suspension cells, either prokaryotic or eukaryotic in type, for both 1 g and microgravity applications. The miniature culture system may advance the development of microanalytical remote monitoring tools such as biological sentinels, biosensors, and lab-on-a-chip. Integrating the autonomous miniature culture system with a microanalytical device makes a powerful biological tool. Cells can be cultured long-term, harvested, and released directly into an analytical tool without the need for human interaction through fluid dynamic manipulations. This work characterizes the miniature bioreactor system through numerical and experimental proof of concept studies.     

空间细胞生物学研究的新进展

空间环境对细胞的影响,对于人类进行长时间探索太空,研究揭示生命的秘密有着重要的意义。而先进的空间细胞培养技术及先进的细胞智能传感技术为我们提供了新的研究手段。文章总结了世界各国近期空间及地面的细胞生物学技术突破及成果,归纳了我国进行空间细胞生物学的研究现状,指出了未来空间细胞生物学的研究热点,给出了空间细胞仪器的设计策略。     

Altered expression of mRNAs implicated in osteogenesis under conditions of simulated microgravity is regulated by CD200:CD200R

Mouse calvarial cells grown under simulated microgravity conditions (neutral buoyancy) show preferential differentiation towards the osteoclast lineage, as defined by surrogate mRNAs, bone nodule growth and TRAP⁺ cells, when compared with cells cultured under normal gravity conditions. This effect was suppressed in cultures which contained the immunoregulatory molecule CD200, and conversely enhanced by anti-CD200 mAb. Concomitant increases occur in expression of inflammatory cytokines, and their mRNAs, under simulated microgravity conditions. Again cultures containing exogenous CD200 showed suppressed cytokine and cytokine mRNA expression. Further alterations in osteoclastogenesis were seen using cells isolated from cytokine-receptor knockout mice. We conclude that, as assessed by altered expression of mRNAs associated with osteoblast differentiation, CD200:CD200R interactions play an important regulatory role in the enhanced osteoclastogenesis seen under simulated microgravity conditions, with changes in cytokine expression further modulating this effect.     

Detection of DNA damages and repair in human culture cells with simulated space radiation

DNA damages and its repair of cultured WI38 human fibroblast cells and T98G human glioblastoma cells were studied by exposing to carbon ion beams of HIMAC accelerator. The exposed cells were incubated at 37 °C for appropriate intervals and the damages were analyzed by alkaline comet assay and quantitative RT-PCR with p53 mRNA Highly inhomogeneous DNA damages were observed among the electrophoretic cell images of the comet assay. The degree of the damages was analyzed semi-quantitatively by using the Comet Index. The damaged fraction of WI38 cells was 85% immediately after 4 Gy (100 keV/μm) irradiation and decreased to 50% after 120 min. incubation indicating a repair of cell DNA. Time dependent p53 gene expression was also analyzed by the quantitative RT-PCR method.     

Parabolic maneuvers of the Swiss Air Force fighter jet F-5E as a research platform for cell culture experiments in microgravity

Long-term sensitivity of human cells to reduced gravity has been supposed since the first Apollo missions and was demonstrated during several space missions in the past. However, little information is available on primary and rapid gravi-responsive elements in mammalian cells. In search of rapid-responsive molecular alterations in mammalian cells, short-term microgravity provided by parabolic flight maneuvers is an ideal way to elucidate such initial and primary effects. Modern biomedical research at the cellular and molecular level requires frequent repetition of experiments that are usually performed in sequences of experiments and analyses. Therefore, a research platform on Earth providing frequent, easy and repeated access to real microgravity for cell culture experiments is strongly desired. For this reason, we developed a research platform onboard the military fighter jet aircraft Northrop F-5E “Tiger II”. The experimental system consists of a programmable and automatically operated system composed of six individual experiment modules, placed in the front compartment, which work completely independent of the aircraft systems. Signal transduction pathways in cultured human cells can be investigated after the addition of an activator solution at the onset of microgravity and a fixative or lysis buffer after termination of microgravity. Before the beginning of a regular military training flight, a parabolic maneuver was executed. After a 1 g control phase, the parabolic maneuver starts at 13,000 ft and at Mach 0.99 airspeed, where a 22 s climb with an acceleration of 2.5g is initiated, following a free-fall ballistic Keplerian trajectory lasting 45 s with an apogee of 27,000 ft at Mach 0.4 airspeed. Temperature, pressure and acceleration are monitored constantly during the entire flight. Cells and activator solutions are kept at 37 °C during the entire experiment until the fixative has been added. The parabolic flight profile provides up to 45 s of microgravity at a quality of 0.05g in all axes. Access time is 30 min before take-off; retrieval time is 30 min after landing. We conclude that using military fighter jets for microgravity research is a valuable tool for frequent and repeated cell culture experiments and therefore for state-of-the art method of biomedical research.     

Taxane recovery from cells of Taxus in micro- and hypergravity

Cell suspension cultures of Taxus cuspidata produce taxanes that are released from the outer surface of cells into the culture medium as free and bound alkaloids. Paclitaxel (Taxol (TM)), is an anti-cancer drug in short supply. It has a taxane ring derived from baccatin III and a C-13 phenylisoserine side-chain. This drug is produced over a wide range of gravitational forces. Monoclonal and polyclonal antibodies to paclitaxel, baccatin III, and the C-13 phenylisoserine side chain were combined in multiple-labeling studies to localize taxanes and paclitaxel on cell surfaces or on particles released into the culture medium. Bioreactor vessel design altered the composition of taxanes recovered from cells in simulated microgravity. At 10(-2) and 2x10(-4)g, taxane recovery was reduced but biomass growth and percent paclitaxel was significantly increased. At 1 to 24g, growth was reduced with a significant recovery of total taxanes with low percent paclitaxel. Bound paclitaxel was also localized in endonuclease-rich fragmenting nuclei of individual apoptotic cells. A model is presented comprising TCH (touch) genes encoding enzymes that modify taxane-bearing xylan residues in cell walls, the calcium-sensing of gravitational forces by the cytoplasm, and the predisposition of nuclei to apoptosis. This integrates the adaptive physiological and biochemical responses of drug-producing genomes with gravitational forces.