Life in Space: the Exploration of Environmental Responses and Robustness of Biological Systems to Predict the Future of Life on and Beyond Earth
“Where do we come from? What are we? Where are we going?”
These timeless questions were posed by the painter Paul Gauguin. Among them, isn't the last one — “Where are we going?” — especially hard to answer?
Yes, the challenge of predicting the future.
But perhaps, as we venture into the frontier of space, we’re beginning to uncover clues to this question — through the lens of life science.
We are living in a singular moment in human history, a time when humanity is stepping into space for the very first time. Why not join us in this exciting journey, where even the outlines of what lies ahead remain undefined?
Let us begin by sharing the background of our research.
Where do we come from? What are we? Where are we going? Paul Gauguin. 1897-1898. Image from MFA Boston: https://www.mfa.org/collections
Background of Study
What happens to life when gravity disappears?
All life on Earth has evolved over the past 4 billion years under the constant influence of 1G gravity. But what kind of changes occur when that familiar force of gravity is removed in space?
From the experience of astronauts, it has long been known that the body’s anti-gravity functions — such as bones and muscles that support posture — rapidly deteriorate in microgravity. It was once assumed that “if gravity is gone, then the functions that resist it are simply no longer needed.”
However, space experiments have revealed much more.
Even fish, which usually live in a buoyant aquatic environment, show changes in their skeletal structure when in space. In mice raised aboard space missions, researchers have observed not only bone and muscle loss, but also changes in the immune system, metabolism, neural function, and even the skin’s barrier function.
Clearly, what’s happening in space goes far beyond the simple loss of anti-gravity functions.
Importantly, these observations have only become possible in recent years, thanks to international collaboration and the establishment of the long-term experimental capabilities of the International Space Station. They represent a completely new realm of scientific knowledge, now accessible for the first time in human history.
Astronauts exercise in space to prevent muscle and bone loss. (Photo from NASA Images)
Is this a reversal of evolution?
What caught our attention was that many of the changes observed in space appear to be related to the functions vertebrates acquired during their evolutionary transition from sea to land.
On Earth, bones become hardened, muscles strengthen, and immune cells are produced in the bone marrow. However, in mice raised in space, bones soften, muscles shrink, and bone marrow cells degenerate.
We also see changes in other functions vital to terrestrial life. The skin’s barrier function, which protects against dryness, and the body’s response to high oxygen levels in the atmosphere — both are altered in space.
It’s as if evolution is being rewound.
These phenomena could be seen as “atavistic phenotypes” — traits resembling those of distant ancestors — could this really be just a coincidence?
Humanity finally reaches space — and the body revert to its ancient form!?
Could it be that the physiological functions we thought were firmly established through evolution are actually not so fixed — but instead, continuously maintained through the organism’s response to gravity?
This is the question that sparked our research.
If that’s the case, then in low-gravity environments such as the Moon (1/6G) or Mars (3/8G), the form and function of Earth-based life might begin to shift into something fundamentally different.
Gravity — something that never disappears on Earth — may have a hidden, yet essential influence on how life maintains its form. This perspective potentially offers a new path forward in evolutionary biology, which has long focused on the stable inheritance of DNA sequences (the genome).
We believe that this research opens the door to integrating environmental influence and memory — including epigenomic information and physical constraints — into our understanding of how life is shaped.
In this project, we aim to uncover the role of the genome and its regulatory systems behind the “atavistic” changes seen in microgravity, and to explore the fundamental role gravity may play in shaping the apparent course of "evolution" and the sustained functions of living organisms.
Could life take on a different shape beyond Earth? (Illustration for conceptual purposes only!)
A New Perspective from Space: Understanding Life on a Cosmic Scale
When we look out into the vastness of space, we’re reminded — often unexpectedly — of just how rare and extraordinary our planet is. Earth’s environment, long taken for granted, is in fact deeply unique.
Beyond gravity, many life-supporting conditions come together here: moderate temperatures and pressure, abundant liquid water, and protection from harsh cosmic radiation thanks to Earth’s magnetic field. Truly, Earth is a “cradle of life” floating in the cosmos.
Yet life on Earth has never existed outside of these conditions. What happens when we leave this familiar environment behind? What might life look like when its surroundings — its very assumptions — are dramatically altered?
These are no longer just speculative questions. Even now, Earth is changing: through climate shifts, environmental degradation, and other pressures. We might soon be able to develop new methods for analyzing these changes, and predicting how they will affect both humanity and the broader ecosystem.
At the same time, in fields like astrobiology—or even in the creation of artificial life and intelligence — if we assume only “Earth-like” life as a model, we may overlook forms of life or intelligence that are already close at hand, simply because we haven’t recognized them for what they are.
To understand the future, we must study the past and present of Earth’s biosphere.
Today, ancient philosophical questions and the frontiers of science are beginning to converge — guided by insights gained from the cosmos.
“Earth” nominated as a Cosmic World Heritage site?
(Caution: not actually registered… yet!)
That was quite a long read — thank you for staying with us! We hope this has helped you get a sense of the background and the questions that drive our work.💦
If you’ve made it this far, perhaps some new thoughts or realizations have already started to form in your mind. From philosophy to social science, from environmental issues to extraterrestrial life — we believe that when each of us takes a moment to reflect,
we can all contribute, in our own way, to building a more sustainable future for both humanity and the Earth’s ecosystems.
Now, we’d love to introduce our final key concept: robustness.... But that’s a big one — so we’ll save it for next time! 😅
For a more detailed introduction to our research(in preparation):
Research Themes and Investigators
Now that the core question and research theme of this project have been defined, the next step is: how do we start to approach it? The answer lies in eight coordinated research programs, each led by a dedicated team of researchers working together to tackle the challenge.
A01: Developmental, physiological, and anatomical approaches
This team focuses on how gravity regulates the body through developmental, physiological, and anatomical mechanisms.
Building on discoveries from JAXA’s mouse spaceflight experiments, they combine space-based findings with ground-based studies. Their goal is to investigate how gravitational cues — such as stimulation of the otolith organs (which sense gravity in inner ear), as well as direct effects on cells and the peripheral nervous system — affect the regulation of various organs throughout the body.
Understanding Gravity Regulation and Space Responses in Skeletal Muscle via the Vestibular and Peripheral Systems
PI: Satrou Takahashi (University of Tsukuba)
Adaptation and Evolution in Bone and Bone Marrow Under Gravity Control and Space Conditions
PI: Masahiro Shinohara (National Rehabilitation Center for Persons with Disabilities)
Immune Regulation Strategies Revealed in Space: Mechanisms and Breakdown under Extraterrestrial Conditions
PI: Taishin Akiyama (RIKEN)
A02: Environmental stress responses, mitochondrial function, and transgenerational effects
This group investigates how environmental stresses—such as altered mitochondrial function and radiation exposure—affect living organisms in space.
Beyond developmental changes, molecular and cellular regulatory systems related to stress responses can shift significantly in space environments.
The team is working to uncover not only these mechanisms, but also how such changes may be passed on to the next generation.
Combating Age-Related Diseases Through Insights into Space Environmental Stress Responses
PI: Takafumi Suzuki (Tohoku University)
Probing Space Environmental Responses Through Cancer Biology Perspectives
PI: Akihisa Takahashi (Gunma University)
Adaptation and Transgenerational Effects in Space: Insights from Mitochondrial Dysfunction Models
PI: Keisuke Yoshida（Nippon Medical School）
A03: Multi-omics and cross-species integration
A03 is responsible for integrating the findings from A01 and A02, along with comprehensive data generated through multi-omics analyses conducted across the project.
This group also includes researchers specializing in non-mammalian models such as plants and microorganisms.
By comparing results across different species, they aim to test and refine hypotheses that emerge from the broader research.
Establishing a Spatial Multi-Omics Platform for Space and Ground-Based Biological Samples
PI: Aya Shiba (University of Tsukuba)
Systems Biology of Epigenomic Flexibility Underlying Robust Adaptive Mechanisms
PI: Masafumi Muratani (Uniersity of Tsukuba)
Study Section: Coordinating Research and Building International Networks
To support collaboration both within and beyond the research area, a Study Section has been established. This body manages coordination across participating teams and allocates resources, with a view toward building an international research network for the post-ISS era. Additional research opportunities will be made available through open calls for JSPS KAKENHI proposals in fiscal years 2025 and 2027. (We encourage eligible researchers to apply!)
Full list of investigators (in preparation).