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Presenting Author(s) Akira Satoh
Abstract Title Muscle formation in Xenopus froglet blastema: making of a muscular spike.
Full author List Akira Satoh Koji Tamura Hiroyuki Ide
Text of abstract

Urodele amphibians have the ability to perfectly regenerate missing body parts, such as jaw, limbs, and tail, throughout their adult life, but the African clawed frog Xenopus laevis, an anuran amphibian, only has a partial ability for regeneration. As developmental stage of Xenopus progresses, the pattern of regenerated structure becomes hypomorphic. Eventually, the froglet and adult frog regenerate a spike-like structure that has a cartilaginous shaft. Cartilage in the spike always shows a cone shape without any branching and segmentation. Moreover, it is known that the spike has little or no muscle, although it has other tissue components such as nerves, blood vessels, dermis and connective tissue. The aim of this study was to determine the reason for the inability of the spike to regenerate muscle.

First, we confirmed that almost all spikes have little muscle tissue. We also compared the expressions of some molecular markers (such as MyoD, myf5, HGF, and cMet) for muscle differentiation in the froglet blastema and the blastema of a stage 52 limb bud, which has the ability for complete regeneration. Then we transplanted an aggregate of muscle satellite cells isolated from froglets into the froglet blastema. The aggregate could differentiate into multinuclear myofibers in the blastema, suggesting that the froglet blastema has a tolerant environment (niche) for muscle differentiation. It is possible that the absence of muscle tissue in the spike is not due to the repressive environment for myogenic proliferation and differentiation but to the absence of muscle precursor cells in the blastema. In order to attract muscle precursor cells into the blastema, we implanted HGF-expressing mouse cells, a P14 cell line, because it is known that HGF has motogenic in limb muscle development. As a result, we succeeded in obtaining muscular spikes that have MF20-positive differentiated muscle tissue.
Which session is your work most relevant to: Limb regeneration