Wnt/FGF20 signaling axis promotes migration of proximal blastema cell during tail regeneration of Gekko japonicus.

The Wnt/FGF20 axis establishes an organizing center that is largely non-proliferative in the distal blastema during epimorphic regeneration across multiple model systems. However, the underlying mechanisms remain poorly characterized. In this study, we investigate the role of the Wnt/FGF20 axis during tail regeneration in Gekko japonicus. We also developed an in vitro system to evaluate the effects of Wnt agonists, FGF20, and FGFR4 on cultured blastema cells. Our results demonstrate that Wnt signaling is activated in distal blastema cells and contributes to a lower proportion of proliferative cells beneath the epidermal basal layer in the regenerating tail of Gekko japonicus. This Wnt-mediated suppression of proliferation is associated with reduced FGFR4 expression, as confirmed both in vitro and in vivo. Furthermore, Wnt pathway activation upregulates FGF20 expression in distal blastema cells, which promotes the migration of proximal blastema cells without affecting their proliferation. Our findings provide an insight into the organizing center of regenerated tissue, revealing a reciprocal regulatory interaction between the epidermis and blastema cells during successful epimorphic regeneration.