NASA’s Ames Research Center in Silicon Valley is sending five biology experiments into space on SpaceX’s 21st commercial cargo resupply mission to the International Space Station. Soon to launch from NASA’s Kennedy Space Center in Florida, the mission will carry mice, cells, and microbes for science investigations that will provide fundamental information about living systems and reveal how biology is different in space. Findings from these studies can help us better understand how to keep astronauts healthy during spaceflight and apply this knowledge to improve life on Earth. 

Here are the five Ames-related experiments launching to the orbiting laboratory:

Spaceflight effects on bone regeneration

Rodent Research-10

Bone health relies on the process of tissue regeneration during which cells continuously break down and build up the structure of bones. The process is akin to removing and replacing rot or termite-damaged beams and boards in a wooden house, so that the whole structure may remain sound over time. Otherwise known in biology as regenerative homeostasis, this process keeps biological systems stable over time. 

The combined effects of bone disuse in microgravity plus space radiation can rapidly disrupt regenerative homeostasis, effectively accelerating bone tissue break down while putting the brakes on bone tissue repair. The net result can be about 1.5% of bone loss per month in gravity dependent bones. This presents health risks for astronauts during spaceflight. As a countermeasure, crew aboard the space station undergo extreme daily physical conditioning of about two hours of bone-loading exercise to maintain bone mass.

Rodent Research-10 investigates the cellular and molecular mechanisms underlying bone regenerative deficits due to disuse on Earth and microgravity in space. The study examines the role of a gene – Cdkn1a – that produces the CDKN1A protein – that inhibits cell cycle progression in cells. 

Stress conditions such as radiation and oxidative stress in microgravity, have been previously shown to induce expression of CDKN1A. This elevation can in turn inhibit the process by which a type of adult stem cells in bone marrow – osteoprecursors – change into a type of bone cell – osteoblasts – that rebuild bone tissue. These actions add up to “applying the brakes” on bone formation, affecting the normal balance of tissue regeneration and leading to net bone loss. 

Rodent Research-10 will study the effects of spaceflight on regenerative bone formation in two strains of mice, wild-type mice that have the Cdkn1a gene, and Cdkn1a-null mice that lack the gene, relative to both strains of mice that remain on Earth. The experiment will test the hypothesis that mice lacking the Cdkn1a gene will show less bone formation deficit in space relative to Earth’s gravity than wild-type mice. If this hypothesis is proven, that would establish the Cdkn1a gene as being required for arresting stem cell-based bone tissue regenerative processes in space. If confirmed, this may become the basis for designing new treatments to counter tissue degeneration in space and lead to novel therapeutic strategies to address bone diseases on Earth

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NASA story: Rodent Research

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Studying spaceflight effects on the eye

Some astronauts experience a condition during long-duration spaceflights in which the eyes show physical changes such as swelling of the eye nerve, and folding, or flattening of the eye ball that  leads to the use of glasses. These changes have the potential to affect astronauts on long-duration human space missions to destinations like Mars. 

Rodent Research-23 will study the effects of spaceflight on the eyes, specifically on the structure and function of the arteries, veins, and lymphatic vessels that are needed to maintain vision. Mice will be housed aboard the station for five weeks and then returned to Earth where researchers will examine the eyes of the mice for changes caused by the time spent in space. 

The information gathered from this study will help scientists to develop effective countermeasures that will protect future astronauts from spaceflight associated eye conditions and are anticipated to shed light on eye diseases found in humans on Earth.

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NASA story: Rodent Research

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Bacteria’ biofilms corrode stainless steel surfaces, poses risks to life support systems

Microorganisms like bacteria often are found attached to surfaces, living in communities known as biofilms. Bacteria within biofilms are protected by a slimy matrix that they secrete. Biofilms can corrode stainless steel surfaces – relevant to stainless steel components of the space station’s water system – and they may become highly resistant to some traditional chemical disinfectants. It is important for the success of NASA’s long duration human spaceflight missions to control microbial growth in the life support system that recycles wastewater into clean water that will be safe for astronauts to drink and use for personal hygiene. 

The Bacterial Adhesion and Corrosion investigation will study the effects of spaceflight on the formation of bacterial biofilms and assess how well disinfectants work to clear them. In addition, this study will help identify which bacterial genes are involved in biofilm growth and corrosion of stainless-steel surfaces in microgravity. Findings from this investigation could provide insight into better ways to control and remove resistant biofilms on Earth and in space, contributing to the success of future long-duration spaceflights.

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Studying nervous system stem cells for clues to increased pressure in the skull

High pressure inside the skull can cause vision problems, headaches, and other serious health problems. Visual problems and headaches have been seen in astronauts during long-duration space missions, and one possible cause could be elevated pressure within the skull. This condition is a challenge during long-duration space exploration missions and is an active area for scientific research. Increased cell division of nervous system cells in spaceflight may play a role in intracranial pressure, or the increased pressure inside the skull. 

BioScience-4 examines the underlying biological mechanisms of two types of nervous system stem cells from the brain; the investigators hypothesize that these cells divide faster in the microgravity environment of space. 

Getting a better understanding of how nervous system stem cells function in microgravity could help scientists develop suitable countermeasures to protect astronauts from problems with intracranial pressure. The findings also could have Earth benefits. Cell replacement therapies would benefit humans with neurological disorders or neurodegenerative diseases, like multiple sclerosis, but are not yet practical because no existing method generates stem cells in sufficient numbers or quickly enough. 

The investigation was flown to the station on SpaceX CRS-16; a portion of the investigation will fly again on SpaceX CRS-21. The second flight will carry samples of one cell type, oligodendrocytes, that are important in the movement of signals along nerves. The neural stem cells that were returned to Earth on SpaceX’s CRS-16 Dragon proliferated more in space and after spaceflight. The second flight experiment will help determine if oligodendrocyte progenitors also proliferate more, and faster, in space. When both cell types used in this study were grown in microgravity analog conditions, they divided faster than cells grown under normal gravity conditions. Studying the reasons why, and the mechanisms causing these cells to divide faster, could pave the way to breakthroughs in stem cell production for cell replacement therapies.

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Health risks of yeast infections in space

For most people, a yeast microbe that is commonly found in the human gut causes an annoyance or no problems at all. But, for those with suppressed immune systems, this yeast can cause an infection that can be dangerous and potentially even life threatening. Because the conditions of spaceflight change the immune systems of humans, astronauts could face higher health risks should they develop infections, including yeast infections. For instance some species of bacteria, have been known to become more dangerous when grown in the spaceflight environment, but we currently understand little about how the environmental stresses of space affect this yeast. 

The Micro-14 investigation builds upon previous flight and ground-based studies, looking for changes in the impact of the yeast on human cells in space and examining how the yeasts are altered under different environmental conditions such as microgravity, oxygen depletion, and carbon dioxide enrichment. 

The study also assesses different drug treatments to compare their effectiveness in treating yeast in the altered environments. Micro-14 was launched to the station on SpaceX CRS-16 and SpaceX CRS-17; a portion of the experiment will fly again on SpaceX CRS-21. Findings from this research will help to identify better methods for controlling and treating yeast infections both in space and on Earth. 

For researchers:

Main image: A SpaceX Falcon 9 rocket lifts off from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida at 12:29 p.m. EST on Dec. 5, 2019, carrying the Dragon spacecraft on the company’s 19th Commercial Resupply Services mission to the International Space Station.