It’s been starved, stabbed, and cut into pieces. Yet this tiny sea creature refuses to die.
It responds to these assaults by rewinding its life cycle, growing younger and younger until it reaches the earliest stage of life. Then, this remarkable jellyfish begins life all over again. No wonder it’s known as the immortal jellyfish.
Could an understanding of how it performs this miraculous feat help humans live forever—or at least longer—too? Researchers believe so. Here’s the fascinating story…
In 1988 a German marine biology student made the accidental discovery that a jellyfish the size of your pinky nail can cheat death when faced with environmental stress or physical assault.
Instead of dying, this jellyfish, named the Turritopsis dohrnii, undergoes a process called reverse metamorphosis – aging backwards – and then begins life again, continually repeating the process.
While this discovery has potentially important implications for treating human disease and aging, the ability to make use of it was hampered because there are so few experts in the world in hydrozoa, the class of marine life the immortal jellyfish belongs to. In addition, these jellyfish are difficult to capture and incredibly hard to culture in a lab.
What has become clear since 1988 is that during reverse metamorphosis T. dohrnii and other species of Turritopsis undergo a process called cellular transdifferentiation.
Essentially, the jellyfish transforms one mature cell into another type of cell as part of a controlled process. For humans, it would be like turning a muscle cell into a kidney cell.
Marine biologist and T. dohrnii expert Maria Pia Miglietta from Texas A&M Galveston explains, saying, “Transdifferentiation occurs when an adult cell matures into another type of cell that is needed at that very moment, and it is generally an important step during regeneration. So, by studying transdifferentiation in T. dohrnii, we can better understand how transdifferentiation works in general.”
She added that the process is poorly understood because it happens in a time frame of only several days.
“This makes it difficult to understand the underpinning genetics of the process,” she said. “But it is so intriguing because this process lets T. dohrnii escape death and it becomes potentially ‘immortal.’ So, our ultimate goal is to understand its life cycle and its genetics that allows it to escape death.”
These cellular changes remind me of pluripotent stem cells and their ability to give rise to any kind of cell in the body.
Anti-aging researchers have long been investigating how to use these stem cells to fight the diseases of aging. And, as you’ll see in a minute, perhaps discoveries from the study of the immortal jellyfish will shed new light in this area. Especially since scientists have found remarkable similarities between jellyfish and people.
Humans Look Like Jellyfish
Shin Kubota, a former associate professor at the Seto Marine Biological Laboratory of Kyoto University, Japan, and, since 2018, director of a private jellyfish research facility, believes the immortal jellyfish holds great promise to fight human aging.
Prof. Kubota has successfully triggered rejuvenation 14 times in one individual jellyfish and dreams of the day when “rejuvenation medicine” can be developed from Turritopsis.
“Once we determine how the jellyfish rejuvenates itself,” explains Prof. Kubota, “it will be easy to solve the mystery of immortality and apply ultimate life to human beings.”
It may seem strange to suggest that humans could find the secret of eternal youth in a creature that has no brain, heart, liver or sensory organs, yet we are not as different as you might imagine.
Dartmouth College molecular paleobiologist Kevin J. Peterson explains, saying, “There’s a shocking amount of genetic similarity between jellyfish and human beings.” From a genetic perspective “we look like a damn jellyfish.”
Of course, this genetic similarity could have important applications in the field of longevity and even cancer treatment.
Potential Breakthrough in Cancer Treatment
Prof. Peterson’s work focuses on microRNAs. These act as an on-off switch to regulate gene expression and are also crucial for the development of the jellyfish.
In the off position, the cell remains primitive and undifferentiated, having no specialized function– just like cancer cells, which are known to have alterations in their microRNA.
In the on position, the cells can mature and turn into a skin cell or liver cell, for instance.
Studying Turritopsis could, therefore, offer a potential breakthrough in cancer treatment and may help us to fight aging, and even prevent death itself.
“Immortality,” said Prof. Peterson, “might be much more common than we think. There are sea sponges out there that we know have been there for decades. Sea-urchin larvae are able to regenerate and continuously give rise to new adults. This might be a general feature of these animals. They never really die.”
Skipping the Stem Cell Stage
Although scientists have reprogrammed cells in adult mice into stem cells so they can restart their life and mature into adult cells, it’s a slow, indirect process with unpredictable outcomes, such as the growth of tumors.
Transdifferentiation, on the other hand, is direct and happens quickly. Older cells can be turned into specialized young cells, skipping the stem cell stage.
Transdifferentiation has already been used in pancreatic cells to produce more insulin, and also shows promise for the treatment of neurodegenerative diseases by replacing lost or damaged brain cells.
So, thanks to the immortal jellyfish, hitting the rewind button on our cells is a real possibility. It could lead to many new treatments for illness and maybe even combat aging itself.