The Immortal Jellyfish: Nature’s Secret to Never Growing Old

When faced with starvation, injury, or old age it performs an extraordinary trick; it reverses its life cycle.

In the calm blue waters of the Mediterranean there exists a creature with an extraordinary ability. The Turritopsis dohrnii carries a title no other creature can claim: the immortal jellyfish. Most animals live, age and die but this jellyfish doesn’t always follow that script. When faced with starvation, injury, or old age it performs an extraordinary trick; it reverses its life cycle. It has captivated scientists and nature enthusiasts alike with its unique talent for turning back the biological clock.

When the Turritopsis dohrnii is faced with threat to its life, it sinks to the ocean floor and begins to decay. The adult jellyfish known as a medusa shrinks its tentacles and retracts its body. Instead of dying, it transforms back into a polyp, its juvenile stage as the cells reaggregate. From that polyp it can grow into an adult again and emerge as a new jellyfish.

This way the jellyfish has skipped to an earlier life stage to begin again.

In most animals including humans once a cell becomes say; a nerve or a muscle cell, it’s locked into that identity. But Turritopsis breaks the rulebook. It can reprogram its cells back to a more primitive stem cell like state giving them a fresh start. This ability comes from a process called trans differentiation where one type of specialized cell changes into another wherein the jellyfish’s cells de-differentiate and specialized muscle, nerve and digestive cells revert to more primitive stem cell like states. Turritopsis is the only animal known to perform it across its entire body repeatedly and theoretically, it could repeat this loop forever.

This is remarkably similar to what scientists do in the lab using induced pluripotent stem cells (iPSCs), a discovery that won the 2012 Nobel Prize. In both cases adult cells regain their ability to become new tissue types.

Studying Turritopsis gives researchers an exemplary biological method for safe cell reprogramming which could help repair damaged organs or rejuvenate aging tissues in humans without triggering uncontrolled growth which is the hallmark of cancer. One of the biggest challenges in regenerative medicine is that rejuvenating cells can lead to tumour formation as cells forget how to stop dividing. What makes this jellyfish astonishing is that it can reprogram its cells repeatedly without turning cancerous. This suggests it has a built in mechanism for controlled regeneration, something researchers are desperate to understand. If scientists decode how the jellyfish balances renewal and regulation it can be used to safely trigger controlled cellular rejuvenation where cells repair themselves without turning cancerous which would revolutionize medicine and also inspire safer cell therapies for humans.

Researchers at the University of Oviedo in Spain have been studying its DNA for many years. In 2022, they identified genes related to DNA repair, stress resistance and cell renewal that are far more active in Turritopsis than in any other jellyfish. These genes may hold clues to how the species maintains its cellular youth as DNA repair, stem cell renewal and stress resistance are the same genetic pathways that are central to human aging research. In fact, DNA repair mechanisms are major focuses of anti-aging biotech companies and longevity labs.

Imagine therapies that rejuvenate old tissues, heal organs or slow degenerative diseases like Alzheimer’s. We are far from that reality but Turritopsis dohrnii is helping scientists imagine it by hinting at biological immortality and challenging our understanding of aging as the jellyfish proves that nature already has a few blueprints for it and offers something no lab experiment can replicate; a naturally evolved system of reversing cellular aging that has survived millions of years. While this fascinating creature might be tiny, its biology holds big clues on how we can slow or even reverse aging in humans, repair damaged tissues or even save human lives!

References:

1. Pascual-Torner, M., Sánchez-Alvarado, A., & Martínez, D. E. (2022). Comparative genomics of mortal and immortal jellyfish species unveils unique genes involved in aging and DNA repair. PNAS, 119(35), e2201275119.

2. Piraino, S., Boero, F., Aeschbach, B., & Schmid, V. (1996). Reversing the life cycle: Medusae transforming into polyps and cell transdifferentiation in Turritopsis nutricula (Cnidaria, Hydrozoa). Biological Bulletin, 190(3), 302–312.

3. Boero, F., & Piraino, S. (2010). The immortality of the jellyfish Turritopsis dohrnii: A model for rejuvenation and longevity. Trends in Ecology & Evolution, 25(8), 403–404.

4. Martínez, D. E. (1998). Mortality patterns suggest lack of senescence in hydra. Experimental Gerontology, 33(3), 217–225.