Regeneration Potential of Jellyfish: Cellular Mechanisms and Molecular Insights.

Sosuke Fujita,Erina Kuranaga,Yu-Ichiro Nakajima

doi:10.3390/genes12050758

Abstract

Medusozoans, the Cnidarian subphylum, have multiple life stages including sessile polyps and free-swimming medusae or jellyfish, which are typically bell-shaped gelatinous zooplanktons that exhibit diverse morphologies. Despite having a relatively complex body structure with well-developed muscles and nervous systems, the adult medusa stage maintains a high regenerative ability that enables organ regeneration as well as whole body reconstitution from the part of the body. This remarkable regeneration potential of jellyfish has long been acknowledged in different species; however, recent studies have begun dissecting the exact processes underpinning regeneration events. In this article, we introduce the current understanding of regeneration mechanisms in medusae, particularly focusing on cellular behaviors during regeneration such as wound healing, blastema formation by stem/progenitor cells or cell fate plasticity, and the organism-level patterning that restores radial symmetry. We also discuss putative molecular mechanisms involved in regeneration processes and introduce a variety of novel model jellyfish species in the effort to understand common principles and diverse mechanisms underlying the regeneration of complex organs and the entire body.

Highlights

Cytaeis uchidae and Rathkea octopunctata have proliferative cells in their tentacle bulbs and manubrium, suggesting the existence of resident stem-like cells in specific compartments [11]. These results indicate that stem/progenitor cell proliferation is a critical factor for medusae organ regeneration
Jellyfish regeneration involves a combination of cellular processes underlying wound healing, blastema formation, and systemic patterning that require organ or body-level communications
Cellular origins of renewing tissues and organs may derive from stem/progenitor cells and/or cell fate plasticity through trans/dedifferentiation of differentiated cells

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The bell-shaped body of a medusa is composed of the following organs: an umbrella for swimming, a manubrium for feeding and digestion, gonads for reproduction, tentacles for capturing prey, and radial canals for nutrient transportation throughout the body (Figure 2B) To control these various organs, medusae have evolved multiple types of muscles (smooth and striated) and an intricate nervous system that include sensory organs with functional eyes (rhopalia) and balance organs (statocysts) [3,7]. In some jellyfish, including the “immortal jellyfish”, Turritopsis dohrnii, adult medusae can transform into cysts after injury or starvation and eventually return to polyps, a phenomenon known as “reverse development” [17,18] These observations indicate that the medusa stage exhibits a high regenerative capacity, which likely varies across different species. We will discuss future directions of research in jellyfish regeneration by sharing unanswered questions and introducing novel model jellyfish species

Wound Healing

Transdifferentiation and Dedifferentiation

Patterning

Findings

Conclusions and Perspectives