Successful reconstitution of the non‐regenerating adult telencephalon by cell transplantation in Xenopus laevis

Abstract

The South African clawed frog (Xenopus laevis) can regenerate the anterior half of the telencephalon only during larval life, but such regeneration is no longer possible after metamorphosis. In order to gain a better understanding of differences between larvae and adults that are potentially related to regeneration, several experiments were conducted on larvae and froglets after the partial removal of the telencephalon. As a result, it was found that the cells in the brain proliferated actively, even in non-regenerating froglets, just as was observed in regenerating larvae after the partial removal of the telencephalon. Moreover, it was shown that although the structure was usually imperfect, even isolated single cells derived from the frog brain were able to reconstitute the lost portion when the cells were transplanted to the partially truncated telencephalon. It is therefore likely to be critical for massive organ regeneration that ependymal layer cells promptly cover the cerebral lateral ventricles at an initial stage of wound healing, as is the case observed in larvae. However, in froglets, these cells strongly adhere to one another, and they are therefore unable to move to seal off the exposed ventricle, which in turn is likely to render the froglet brain non-regenerative.

Cellular response after crush injury in adult zebrafish spinal cord

“…In the case of zebrafish, even crush injury, which involves ependymal disruption, can cause ependymal sealing and formation of the ependymal bulb. Our evidence also suggests the importance of ependymal sealing in spinal cord regeneration, since it was shown in an earlier study that delayed and imperfect sealing of ependyma at the lesion site by ependymal cells is an important contributing factor leading to loss of the regeneration capacity of post-metamorphic frog after telencephalic injury (Yoshino and Tochinai, 2004).…”

Regeneration of Xenopus laevis spinal cord requires Sox2/3 expressing cells

“…S3). Double labeling for Sox2 and BrdU was performed as described (Yoshino and Tochinai, 2004). Mouse monoclonal anti-BrdU was used (1:50, Roche, 11170376001).…”

Neuronal Regeneration from Ependymo-Radial Glial Cells: Cook, Little Pot, Cook!

“…The gradual cessation of regenerative capacity at the onset of metamorphosis is studied mostly in the African clawed toad (Xenopus laevis) (Bernardini et al, 2010;Lee-Liu et al, 2014;Yoshino and Tochinai, 2004). Interestingly, there is also a non-regenerative period during larval development of the Xenopus tadpole, before and after which tail regeneration, including spinal cord, occurs (Beck et al, 2003).…”