MICROSCOPY & IMAGING
Type IV cell chamber with outer shell
microgravity, could pave the way to breakthroughs in stem cell production for cell replacement therapies. Finding ways to generate more stem cells is urgent, because there is currently no way to quickly produce the large numbers of stem cells needed for the many cell replacement therapies that are showing such promise for people with neurological disorders or neurological diseases such as multiple sclerosis or developmental disabilities. In addition, using one’s own cells without grafting opens up the possibility that a neural stem cell donor could be his or her own recipient, eliminating any risks of rejection. Such an approach could be used for head and spinal injuries, as well as other cell replacement therapies. In addition to her work with NASA, Dr Espinosa-Jeffrey would like to work on these issues with the Center for the Advancement of Science in Space (CASIS), which is pursuing research on the effects of microgravity on cells to better study diseases and therapies aimed at prevention and treatment.
EXPERIMENT DETAILS Te NASA experiment, dubbed BioScience-04: Te Impact of Real Microgravity on the Proliferation of Human Neural Stem Cells and Derived- Oligodendrocytes, launched in the Space-X 16 Dragon capsule in December 2018. Two types of cells were studied – neural stem cells and oligodendrocyte progenitor cells. Neural stem cells produce all three major nervous system cell types: neurons, and the two kinds of cells that support neurons – astrocytes and
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oligodendrocytes. Neural stem cells also produce progenitor cells, which are like stem cells because they divide to produce new cells but are more limited because they cannot divide and produce new cells indefinitely. One kind of progenitor cell produced by neural stem cells is the oligodendrocyte progenitor cell, which become mature oligodendrocytes. Oligodendrocytes form electrical insulating membranes known as myelin sheaths that coil around neuronal axons, allowing signals to move along nerves at normal speeds, and making these cells vitally important to nervous system health. Testing whether these important cells divide faster into two daughter cells in the microgravity environment of space, the experiment is helping scientists study the cell signalling pathways that determine cell function, proliferation, and differentiation.
Te two cell types were sent to the
International Space Station in cell culture hardware developed by Airbus-Kiwi, rented from Airbus, and then installed in the Space Technology and Advanced Research Systems (STaARS)-1 Experiment Facility, where the cells were given time to grow and divide. Espinosa-Jeffrey created the experiments and inspired the STaARS team to design the self-contained box, controlling and automating the culture media exchanges from Houston, Texas, so astronauts would not have to invest time on this task.
Te experiment had to deal with delays; splashdown was 39.3 days instead of 35 days originally anticipated. After splashdown, transport to Long Beach airport, and delivery to UCLA, the human
neural stem cells were retrieved from the hardware, plated onto poly-d-lysine- coated flasks in a proprietary stem cell chemically defined medium, and allowed to recover from space flight. Researchers then began measuring how much the cells had divided while in space as well as after space flight and identifying the proteins secreted. Tis work is still in progress. It was extremely important to begin analysis immediately, so there would be no chance of missing any changes to the cells. “It was important that we were able to show that cells behaved like in simulated microgravity, where some cells move slightly faster,” says Espinosa-Jeffrey. “Checking data from time-lapse images we could see that cells had proliferated post flight. Tis means that both the cells that came back and their progenies “remember” being in space. Te daughter cells keep proliferating, but we do not yet know the mechanism by which this is happening.” Te team is characterising features that differ from their simulated microgravity studies.
DEDICATED MICROSCOPE RESOURCES NEEDED Although Espinosa-Jeffrey was able to complete a portion of the analyses needed to study the brain cells that had been in space, other studies required specialised microscopy hardware to which she did not have sufficient access. In particular, there was a great deal of competition for equipment needed to perform time- lapse imaging to confirm the cells indeed proliferate more and provide data on all the properties they show. To get the data on cells, time-lapse studies had to be performed over a period of at least 72 hours. During this time the cells had to be sustained in a controlled temperature and gas environment that is
Human neural stem cells
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