Investigating the developmental onset of regenerative potential in the annelidCapitella teleta

Abstract

An animal's ability to regrow lost tissues or structures can vary greatly during its life cycle. The annelid Capitella teleta has robust posterior, but not anterior, regeneration as a juvenile and an adult. In contrast, embryos display only limited replacement of specific tissues. To investigate when during development C. teleta becomes capable of regeneration, we assessed the extent to which larvae can regenerate. We hypothesized that larvae exhibit intermediate regeneration potential and demonstrate some features of juvenile regeneration, but do not successfully replace all lost structures. Both anterior and posterior regeneration potential of larvae were evaluated following amputation. Responses were analyzed by EdU incorporation, immunohistochemistry, phalloidin staining, and in situ hybridization. Wound sites were evaluated for re-epithelialization, cell proliferation, stem cell marker expression, the presence of neurites and regrowth of structures. Wound healing occurred within 6 hours of amputation. Cell proliferation at the wound site was observed for up to 7 days following amputation. In addition, the stem cell marker vasa was expressed at anterior and posterior wound sites. However, growth of new tissue was observed only in posterior amputations. Neurites from the ventral nerve cord were also observed at posterior wound sites. De novo ash expression in the ectoderm of anterior wound sites indicated neuronal cell specification, although the absence of elav expression indicated an inability to progress to neuronal differentiation. In rare instances, cilia and eyes reformed. Both amputations induced ectopic expression of the myogenesis gene myoD. Our results indicate that amputated larvae complete early, but not late, stages of regeneration, indicating a gradual acquisition of regenerative ability in C. teleta. Furthermore, amputated larvae can metamorphose into burrowing juveniles, including those missing brain and anterior sensory structures. To our knowledge, this is the first study to assess regenerative potential of annelid larvae.

The cost and payout of age on germline regeneration and sexual maturation inPlatynereis dumerilii

“…In Ciona intestinalis , rate of regeneration decreases as the adult body size increases (Dahlberg et al, 2009). While declining regeneration with increasing age seems to indicate younger means more regenerative, being too young may work against regeneration as well: larval stages lack regenerative ability in many animals that can extensively regenerate as adults (Boyd and Seaver, 2023; Henry and Hart, 2005; Jeffery, 2015). Therefore, age and developmental stage are important intrinsic factors affecting regenerative potential in a given species, but which developmental stage or what age is most permissive to regeneration depends on the species.…”