Immortal jellyfish may prevent human aging, research says

Re-specializing the 'immortal' jellyfish

The Independent reported that Maria Pascual-Torner and her colleagues at Spain’s University of Oviedo examined the genomes of the immortal jelly to a closely related species, Turritopsis rubra, the crimson jellyfish, which cannot reverse its aging process as easily.

Looking at the two medusas, researchers discovered that the immortal jellyfish had mutations that allowed it to limit cell division and prevent telomeres, the protective caps over the chromosomes, from breaking down. It also had two times the number of genes linked to DNA repair and protection.

In addition to silencing developmental genes to revert to their earlier forms, the immortal jellyfish also triggered additional genes that allowed the reverted cells to "re-specialize" as the colony split off into swimming individuals once again.

More specifically, medusae, or adult jellyfish, reverse their genetic clock to become larval once more when they perceive a threat from changing environmental conditions. They are merely a thin layer of cells and tissue that float through the water in search of a rock or seagrass blade to cling to.

Are humans closer to immortality?

The scientists expressed hope that their genome mapping might result in discoveries on human aging and initiatives to lengthen life expectancy, as reported in The Wall Street Journal.

"It’s a mistake to think we will have immortality like this jellyfish because we are not jellyfish,” she said. But it’s possible something in the immortal jellyfish’s evolutionary trick can be used to better understand the pathologies of aging," Pascual-Torner said.

The study contained an important message about extending an organism's health span, or healthy years, according to Dr. Jan Karlseder, a molecular biologist and director of the Glenn Center for Biology of Aging Research at the Salk Institute.

"The most interesting thing is that it’s not a single molecular pathway…It is a combination of many of them,” he said.

"If we want to look for an extension of healthspan, we cannot just focus on one pathway. That will not be sufficient. We need to look at many of them and how they synergize," he added.

Study abstract

Turritopsis dohrnii is the only metazoan able to rejuvenate repeatedly after its medusae reproduce, hinting at biological immortality and challenging our understanding of aging. We present and compare whole-genome assemblies of T. dohrnii and the nonimmortal Turritopsis rubra using automatic and manual annotations, together with the transcriptome of life cycle reversal (LCR) process of T. dohrnii. We have identified variants and expansions of genes associated with replication, DNA repair, telomere maintenance, redox environment, stem cell population, and intercellular communication. Moreover, we have found silencing of polycomb repressive complex 2 targets and activation of pluripotency targets during LCR, which points to these transcription factors as pluripotency inducers in T. dohrnii. Accordingly, we propose these factors as key elements in the ability of T. dohrnii to undergo rejuvenation.