Study identifies two stem cell types driving jellyfish tentacle growth


A type of jellyfish about the size of a little fingernail cladonema A severed tentacle can regrow in 2-3 days – but how? Regeneration of functional tissues across species, such as salamanders and insects, relies on the ability to repair damage and form blastocytes, masses of undifferentiated cells that grow into lost appendages. Jellyfish, like other cnidarians such as corals and sea anemones, exhibit high regenerative abilities, but how their vital blastema cells are formed has remained a mystery until now.

A Japanese research team has revealed the existence of stem-like proliferating cells. Actively proliferating and dividing, but not yet differentiated into specific cell types – appear at the site of injury and help form a blastoma.

The research results were published in a scientific journal PLOS Biology.

Importantly, these stem-like proliferating cells in the blastema are distinct from the resident stem cells localized in the tentacles. Repair-specific proliferating cells primarily contribute to the epithelium. Thin outer layer -; newly formed tentacles. ”


Yuichiro Nakajima (Corresponding author, Lecturer, Graduate School of Pharmaceutical Sciences, University of Tokyo)

According to Nakajima, the resident stem cells present in and near the tentacles are responsible for generating all cell lineages during homeostasis and regeneration, and maintain all the cells needed throughout the jellyfish’s life. means to repair. Repair-specific proliferating cells appear only upon injury.

“The combination of resident stem cells and repair-specific proliferating cells enables rapid regeneration of functional tentacles within a few days,” Professor Nakajima said, adding that jellyfish use their tentacles to hunt and feed. It pointed out.

According to lead author Sosuke Fujita, a postdoctoral researcher in the same laboratory as Nakajima at the Graduate School of Pharmaceutical Sciences, the discovery will help researchers understand how blastoma formation differs between different animal groups. It shows that you understand.

“In this study, our aim was to use the tentacles of the cnidarian jellyfish to address the mechanisms of blastogenesis. cladonema “As a model for regeneration in non-bilateral animals, or animals that do not form bilaterally – or from left to right – during embryonic development,” Fujita said, explaining that the study could provide insights from an evolutionary perspective. did.

For example, salamanders are bilaterally symmetrical animals that can regenerate limbs. Their limbs contain stem cells that are restricted to the needs of specific cell types, and this process is thought to function similarly to the repair-specific proliferating cells observed in jellyfish.

“Given that repair-specific proliferating cells are similar to restricted stem cells in the limbs of bilateral salamanders, the formation of blastema by repair-specific proliferating cells has been linked to complex organs and appendages during animal evolution. We can infer that this is a common feature that was acquired independently for organ regeneration,” said Fujita. Said.

However, the cellular origin of the repair-specific proliferating cells observed in blastema cells remains unclear, and researchers believe that the tools currently available to investigate their origin are too limited. They say they are unable to elucidate or identify other distinct stem-like cells. cell.

“It is essential to introduce genetic tools that allow tracing and intracellular manipulation of specific cell lineages. cladonema“Ultimately, understanding the mechanisms of blastogenesis in regenerating animals, including jellyfish, may help us identify cellular and molecular components that improve our own regenerative abilities.” Professor Nakajima said.

Funding:

This research was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science, the Japan Science and Technology Agency, the Japan Agency for Medical Research and Development, and a grant from the National Institute for Basic Biology Joint Research Project.

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Reference magazines:

Tetsuya Fujita other. (2023). A unique stem-like cell population promotes functional regeneration of Cladonema medusa tentacles. PLOS Biology. doi.org/10.1371/journal.pbio.3002435.



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