High Throughput Pan-omic Approaches to Study the Effect of Microgravity on Responses of Skin Endothelial Cells to Insult (STL-MRMC) - 07.14.16
Space Tissue Loss is a DoD Space Test Program payload flying both DoD and NASA science that uses cell and tissue cultures in microgravity to study the effects of tissue regeneration and wound healing in space. Science Results for Everyone
Advantage: pathogens. In microgravity, some bacteria become stronger while the human immune system becomes weaker. This investigation detected suppression of genes involved in the ability of human cells to recognize bacterial toxins, causing a delayed and weak response to bacterial invasion. Other cell functions, including division, normal growth and death, also were affected. Analysis revealed impaired healing and defects in the creation of new blood vessels necessary for healing. Further investigation into immune response at the cellular level could provide valuable insight for preventing infections and promoting healing in space and on Earth. Experiment Details
Rasha Hammamieh, Ph.D., United States Army, Ft. Detrick, MD, United States
Nabarun M. Chakraborty, M.S., M.B.A., US Army, Ft. Detrick, MD, United States
Marti Jett, Ph.D., United States Army, Ft. Detrick, MD, United States
Aarti Gautam, Ph.D., Ft. Detrick, Ft. Detrick, MD, United States
Telemedicine and Advanced Technology Research Center, Ft. Detrick, MD, United States
United States Department of Defense Space Test Program, Johnson Space Center, Houston, TX, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
National Laboratory - Department of Defense (NL-DoD)
ISS Expedition Duration
March 2011 - September 2011
Versions of STL experiments and CCM have flown on the following Shuttle missions: STS-45, STS-53, STS-56, STS-59 (two units), STS-63, STS-66, STS-69, STS-70, STS-72, STS-77, STS-78, STS-80, STS-86, STS-93 (two units), STS-95, STS-118, and STS-131.
- The MRMC (Medical Research and Materiel Command) Department of Defense Space Test Program payload investigates the effect of microgravity on an in vitro wound model caused by an endotoxin insult.
- These experiments aim to help in understanding the effect of altered gravitational force on host responses to injury and to identify molecular signatures associated with such cellular damage in skin/dermal endothelial cells.
- This study can potentially reveal biological signatures that may guide instituting ‘early’ therapeutic measures against impaired healing processes subjected to altered gravitational conditions.
Previous studies suggest that continuous exposure to microgravity during spaceflight develops an immunocompromised host, thus significantly delaying the wound healing process. Compromised healing cascade meets further challenges as microgavity tends to have a complementary effect on bacterial cell growth. Comprehensive knowledge of the healing etiology submitted to the dual stressors is eminent, but presently elusive. Towards this objective, an in vitro model of endotoxin assaulted dermal cellular system is proposed to investigate under altered gravitational force.
Briefly, the endothelial cells will be seeded onto hollow-fiber bioreactors and perfused. Lippopolysaccharide (LPS), an endotoxin commonly associated with gram negative bacteria, will be injected into the test samples during the flight and the reaction will be stopped at two different time intervals. High throughput gene, microRNA, metabolite and protein expression analyses will be carried out to characterize the molecular signatures associated with the temporal response of the gravity-compromised endothelial cells towards the endotoxin.
Identified signatures at transcriptomic, miRNA, proteomic and metabolomic levels will be further compared with the database generated through the ground level study associated with similar cell based insult.
The proposed experiments will expand the system biological knowledge in the following aspects associated with in vitro wound model subjected to microgravity:
1. Omics-based temporal molecular markers/ therapeutic targets associated with endotoxin induced dermal blood microvascular endothelial cell injury.
2. Key biological networks/ nodes/ downstream ‘disease footprints’ associated with LPS-induced endothelial cell injury.
3. A comparative analysis of wound model developed in space and at ground to identify factors that are key regulators or components of differentiation.
The Cell Culture Module (CCM) hardware used in STL is designed specifically to study the effects of microgravity on cell culture. For this experiment, off-the-shelf hollow fiber bioreactors are used as basic cell support structures. The CCM allows controlled physiologic maintenance, manipulation, and testing of the cells. STL is made up of three experiments that will be conducted inside the CCM. The CCM is a completely automated, temperature controlled system designed to help scientists study the effects of microgravity on cells in space. The study includes cultured tissue test materials in continuous flow modules.
- The units are self-contained; operation and data logging is automated.
- The tissues are cultured in hollow fiber bioreactors to allow facile sampling of metabolites and waste products and easy application of candidate pharmaceuticals.
- The experiment's cultured cells are maintained in an optimum growth and maintenance environment, including feedback control of temperature, oxygen concentration, pH, nutrient delivery, flow rate, pulsatile diffusion, and shear. These highly controlled and reproducible tissue models will be challenged with a variety of growth factors, regenerative cell populations, and biomaterials.
Prolonged residence in a space shuttle causes immunocompromisation; therefore the astronauts not only suffer from a delayed healing process, they also become particularly vulnerable to bacterial infection. This study is designed to identify certain early molecular signatures and/or therapeutic targets associated with the compromised healing cascade.
Wound healing is considered a major clinical challenge in surgical and military units; the related concerns have been mounting recently, triggered by an aging population and increasing rates of diabetes, obesity and cancer treatment side effects. To better understand the physiological cascade of the healing model, the present plan intends to temporally obtain in vitro biological samples associated with endotoxin insulted dermal cells and identify molecular signatures using an integrated pan-omics platform. We project that the earth based pan-omic study may reveal true EARLY (or "immediate onset") indicators of the healing cascade; but, perhaps more importantly, a demonstrable understanding of the regulatory nodes/networks cascading into successful wound healing.
Operational Requirements and Protocols
Four rails with individual flow paths and bioreactors will be housed inside the CCM hardware. Two rails will be used for the NASA investigator and two rails will be shared between the DoD investigators. The configuration will allow for redundancy in experiments, increasing the probability of successful tests and samples returning to earth for analysis.
The STL investigation is self contained and requires crew interaction for activation, status checks, and re-entry. Rails will contain cell lines treated with different agents. Following the return to Earth, the rails will be returned to the investigator for in-depth analysis.
Decadal Survey Recommendations
Information Pending^ back to top
Microgravity (μG) likes to help some bacteria grow faster and become more dangerous; at the same time, it can suppress the human immune system, thereby increase the chance for infections and disease. The purpose of this experiment was to understand the impact of μG on the immune response of cultured human skin endothelial cells upon exposure to Lipopolysaccharides (LPS) - bacterial endotoxins found in the outer membrane of Gram-negative bacteria. Cultured endothelial cells were introduced to LPS, for 4 hours and 8 hours, during spaceflight then dissolved in situ for genetic and protein studies. In principal, this customized method helped to isolate the cellular molecular markers of the immune response in μG. Results revealed a weakened immune response in microgravity, as seen by the suppression of genes that make proteins responsible for early LPS uptake. Normal early pathogenic detection was feeble and delayed in spaceflight. Longer LPS exposure meant a delayed host response and prevention of opportunistic bacterial invasion. Downstream normal cell cycles (death, division, and growth) were negatively affected, as well. Impaired healing and defective angiogenesis (the creation of new blood vessels necessary for healing) were other significant findings from protein analysis. A synergistic immune blunting was evident in spaceflight. Taken together, a more comprehensive follow up assessment is necessary to validate these observations.^ back to top
Ground Based Results Publications
NASA Image: S118E10350 - Seen in this image is the hardware that houses the Cell Culture Module - Immune Response of Human Monocytes in Microgravity (CCM-Immune Response) and the Cell Culture Module - Effect of Microgravity on Wound Repair: In Vitro Model of New Blood Vessel Development (CCM-Wound Repair) experiments. The experiments were flown on STS118/13A.1 in August 2007.
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