Nav: Home

Gravitational biology

January 10, 2017

Space travel in a reduced gravity environment can have lasting effects on the body. For example, researches clearly show that astronauts undergo a significant drop in bone mineral density during space missions, but the precise molecular mechanisms responsible for such changes in bone structure are unclear.

Now, Akira Kudo at Tokyo Tech, together with scientists in Japan in support of other countries, performed remotely live-imaging (real time) for fluorescent signals derived from osteoblasts and osteoclasts of medaka fish after only one day of exposure to microgravity aboard the International Space Station (ISS). They found increases in both osteoblast and osteoclast specific promoter-driven GFP and DsRed signals one day after launch, and continued for up to eight days.

In their experiments, the team used four different double medaka transgenic lines focusing on up-regulation of fluorescent signals of osteoblasts and osteoclasts to clarify the effect of gravity on the interaction of osteoblast-osteoclast. They also studied changes in the gene expression in the transgenic fish by so-celled transcriptome analysis.

These findings suggest that exposure to microgravity induced an immediate "dynamic alteration of gene expressions in osteoblasts and osteoclasts." Namely, these experiments based on real time imaging of medaka from Earth and transcriptome analysis could be the prelude to the establishment of a new scientific areas of research in "gravitational biology".?


The live-imaging of fluorescence microscopy signals from the fish aboard the ISS were monitored remotely from Tsukuba Space Center in Japan.

Live-imaging of osteoblasts showed the intensity of osterix- and osteocalcin-DsRed in pharyngeal bones to increase one day after launch. This increased effect continued for eight days for osterix- and 5 days for osteocalcin.

In the case of osteoclasts, the fluorescent signals observed from TRAP-GFP and MMP9-DsRed increased significantly on the fourth and sixth days after launch.

The fluorescent analysis was complimented by using transcriptome analysis to measure gene expression in the transgenic fish. The researchers state that, "HiSeq from pharyngeal bones of juvenile fish at day 2 after launch showed up-regulation of 2 osteoblast- and 3 osteoclast- related genes".

Also, transcription of the "nucleus" was found to be significantly enhanced based on whole body gene ontology analysis of RNA-Seq, with the researchers observing transcription-regulators to be more up-regulated at day 2 compared with during day 6.

Finally, Kudo and the team identified 5 genes: (c-fos and jun-b, pai-1 and ddit4, and tsc22d3) that were all up-regulated in the whole-body on days 2 and 6, and in the pharyngeal bone on day 2.


Live in so-called 'microgravity' environments -- where the force of gravity is considerably less than on Earth -- can cause significant problems for the human body. Astronauts who spend a number of months in space have been shown to suffer from reduced bone mineral density, leading to skeletal problems. Surprisingly, the loss of calcium starts at least 10 days after launch in astronauts in Skylab Flights, as to symptoms that appear early in orbit.

The precise molecular mechanisms responsible for loss of bone density are not yet fully understood. The current study by Kudo and his team is a major step towards uncovering the mechanisms governing changes in bone structure immediately after the onset of microgravity, when bone loss is triggered. By remote live-imaging from Tsukuba Space Center of the behavior of medaka on board the ISS, they found significant increases in both osteoblast and osteoclast specific promoter-driven GFP and DsRed after exposure to microgravity. The findings imply that changes in osteoblasts and osteoclasts occur very soon after launch.


In the next space experiment, Kudo and colleagues will clarify the role of glucocorticoid receptor (GR) on cells in microgravity.

Tokyo Institute of Technology

Related Microgravity Articles:

Graphene sets sail in microgravity
ESA-backed researchers demonstrate the laser-propulsion of graphene sails in microgravity.
Long spaceflights affect astronaut brain volume
Extended periods in space have long been known to cause vision problems in astronauts.
Space travel can make the gut leaky
Bacteria, fungi, and viruses can enter our gut through the food we eat.
Cancer research that's out-of-this-world
University of Technology (UTS) researcher Dr. Joshua Chou is looking to replicate the promising results of experiments he has carried out on cancer cells in the zero gravity chamber built by his team in the UTS School of Biomedical Engineering.
Study underscores changes in brain structure, function in long-duration space missions
New study demonstrates for the first time that changes in cognitive performance correlate with changes in brain structure in NASA astronauts following spaceflight.
Microgravity changes brain connectivity
An international team of Russian and Belgian researchers, including scientists from HSE University, has found out that space travel has a significant impact on the brain: they discovered that cosmonauts demonstrate changes in brain connectivity related to perception and movement.
Frozen sperm retains its viability in outer space conditions
Zillionaires like Amazon founder Jeff Bezos who see the 'colonization' of space as an answer to the Earth's ever threatened resources will be reassured to learn that human sperm retains its complete viability within the different gravitational conditions found in outer space.
In vivo data show effects of spaceflight microgravity on stem cells and tissue regeneration
A new review of data from 12 spaceflight experiments and simulated microgravity studies has shown that microgravity does not have a negative effect on stem-like cell-dependent tissue regeneration in newts, but in some tissues regeneration is faster and more robust.
Universal laws in impact dynamics of dust agglomerates under microgravity conditions
A collaboration between Nagoya University and TU Braunschweig finds evidence that when projectiles hit soft clumps of dust or hard clumps of loose glass beads, the scaling laws for energy dissipation and energy transfer are the same in each case.
'Dust up' on International Space Station hints at sources of structure
In a lab on Earth, electrically charged dust generally lines up either along the downward pull of gravity or across it.
More Microgravity News and Microgravity Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Making Amends
What makes a true apology? What does it mean to make amends for past mistakes? This hour, TED speakers explore how repairing the wrongs of the past is the first step toward healing for the future. Guests include historian and preservationist Brent Leggs, law professor Martha Minow, librarian Dawn Wacek, and playwright V (formerly Eve Ensler).
Now Playing: Science for the People

#566 Is Your Gut Leaking?
This week we're busting the human gut wide open with Dr. Alessio Fasano from the Center for Celiac Research and Treatment at Massachusetts General Hospital. Join host Anika Hazra for our discussion separating fact from fiction on the controversial topic of leaky gut syndrome. We cover everything from what causes a leaky gut to interpreting the results of a gut microbiome test! Related links: Center for Celiac Research and Treatment website and their YouTube channel
Now Playing: Radiolab

The Flag and the Fury
How do you actually make change in the world? For 126 years, Mississippi has had the Confederate battle flag on their state flag, and they were the last state in the nation where that emblem remained "officially" flying.  A few days ago, that flag came down. A few days before that, it coming down would have seemed impossible. We dive into the story behind this de-flagging: a journey involving a clash of histories, designs, families, and even cheerleading. This show is a collaboration with OSM Audio. Kiese Laymon's memoir Heavy is here. And the Hospitality Flag webpage is here.