Tardigrades are the undisputed masters of survival. Bake them at 300 degrees Fahrenheit, freeze them to within a degree of absolute zero, deprive them of water and oxygen, subject them to the vacuum of space — they will still survive. And now scientists have begun to show how we can harness their legendary resilience to advance human medicine.
Inspired by the feats of these near-microscopic animals (also known as water bears), researchers at the University of Wyoming wanted to see what would happen if they introduced a particular tardigrade protein into isolated human cells. Incredibly, even in such a foreign context, it had the same effect: The cells slowed their molecular processes, resulting in a sort of suspended animation that protected them from harm.
These findings point to the potential for tardigrade biology to extend the shelf-life of medicines, to halt tissue decay from injuries, and perhaps even to slow the aging process. They were published in the journal Protein Science earlier this year, with Silvia Sanchez-Martinez, a senior research scientist in the lab of molecular biologist Thomas Boothby, as the paper’s lead author.
“If we learn the tricks [tardigrades] use to survive these extreme environments,” Sanchez-Martinez says, “maybe we can use those to our advantage.”
Studying Tarigrade Biostasis
When times get tough, tardigrades enter a remarkable liminal state called biostasis: Their metabolism ceases, as does their need for food, water, and pretty much everything else we generally consider necessary for life. They can wait like that indefinitely, but as soon as their fortunes improve, they bounce right back. Some have been revived after decades, good as new.
One of the crucial tricks behind these death-defying stunts is a protein called Cytoplasmic Abundant Heat Soluble (CAHS), which comes to the rescue during periods of environmental stress. Most proteins have a highly ordered structure and can’t tolerate much environmental stress without unraveling. But this one (which hasn’t been found in any other animal) is intrinsically disordered, allowing it to function under almost any circumstances.
Even though our last common ancestor with tardigrades lived some 600 million years ago, we make excellent use of the gene that enables this process. When third-year graduate student Kenny Nguyen introduced it to human cells, the gel not only formed just as it does in its native physiology, but also conferred the same advantages: The cells were better able to withstand desiccation and retain their normal functions.
“Seeing that you can put it into a different system and it’s able to survive stress,” Nguyen says, “that’s pretty cool.”
Biostasis is a handy strategy, but only if it’s reversible. When a dried out tardigrade encounters water — that is, when conditions are again suitable for life — the CAHS gel quickly dissolves and the creature’s metabolism restarts.
“In about an hour or so,” Sanchez-Martinez says, “they are moving around the plate like nothing has happened,” even if they’ve been dormant for years.
Sanchez-Martinez wasn’t sure what to expect from human cells, and was rather astonished to find they returned to business as usual once they were rehydrated.
Read More: Can the Cute Tardigrade Survive in Space?
Applying Biostasis to Humans
This might sound like the prelude to a sci-fi tale of deathless human-tardigrade hybrids, but the reality is more mundane.
“It’s not to live forever or to make ourselves immortal,” Sanchez-Martinez says with a laugh. But CAHS could prove useful in emergency scenarios, by pressing pause on tissue decay. During organ transplants, for example, or in the trauma medicine of war zones, “we can stop or halt some of the injuries until we can address them properly.”
Another promising application for CAHS, at least in the near future, is to preserve the myriad biologic medicines that undergird countless global health initiatives. These diverse pharmaceuticals (which include vaccines, blood products and gene therapies) are derived from living organisms, and like all biological material they’re relatively unstable. Adverse conditions quickly degrade the RNA, DNA, and proteins from which they’re built.
As it stands, biologics are dependent on the cold chain, or a global network of freezers that keeps things refrigerated during transportation, storage, and distribution. (It’s the same frigid web that carries seafood dubiously deep into the American heartland.)
But that infrastructure is expensive to build and maintain, not to mention far from foolproof — one brief power outage can ruin a supply of life-saving medicine.
Our diminutive heroes may be leading the way to a world where drugs don’t need constant chilling.
“Tardigrades are made up of all the same things,” Boothby says, “and yet they are able to stabilize these very fragile molecules, using their superpowers.”
With some help from wonder-proteins like CAHS, scientists may be able to engineer a line of biologics that can be preserved in a dry state, making medical treatment more accessible in remote and underdeveloped regions.
Read More: Life After Death? Cryonicists Try To Defy Mortality By Freezing Bodies
Continuing Research on CAHS
The researchers have already shown that CAHS can preserve human blood clotting factor VIII, a biologic commonly used to treat hemophilia and cases of extreme bleeding on the battlefield.
In March 2023, in the journal Scientific Reports, the team unveiled a version of the drug that was stable not just at room temperature, but at any temperature it’s likely to encounter.
“We can heat them up to […] almost the boiling point of water,” Boothby says, “and they actually stay totally effective.”
That research grew out of a project sponsored by the Defense Advanced Research Projects Agency, or DARPA, which develops new technologies for the U.S. military. The lab has already started testing the drug on mice, and Boothby hopes human trials will follow within the next couple years.
But even if we can’t transform ourselves into human-sized water bears any time soon, the realistic possibilities are just as captivating. “This isn’t science fiction,” he says, “this is science fact.”
Read More: Could Tardigrades Have Colonized The Moon?
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Cody Cottier is a contributing writer at Discover who loves exploring big questions about the universe and our home planet, the nature of consciousness, the ethical implications of science and more. He holds a bachelor’s degree in journalism and media production from Washington State University.
Source : Discovermagazine
