19-P008 SHH is a master regulator of stem cell-driven continuous growth of the mouse incisor

in vertebrates and to determine the molecular and cellular basis for such currents. Methods: We use zebrafish caudal fin as an adult regeneration model. Specific ion flux measurements are done using a non-invasive Ion-Specific Scanning Microprobe coupled with transcriptional profiling and genetic functional analysis. Results: Our data points to an important role for protons (H[+]) during the regeneration process. H[+] effluxes are triggered during wound healing and maintained throughout regeneration. Microarray analysis revealed the proton pump V-ATPase as a putative mediator of such H[+] fluxes and we observed that it is expressed in the blastema. We are now exploring this proton-based mechanism with genetic and pharmacological approaches coupled with advanced pH imaging. Other ions are also under study. Conclusions: Overall, our results reveal that important ion-driven mechanisms underlie adult tissue regeneration and its comprehension may open way for new therapeutic strategies and drug screenings, both in regenerative and developmental medicine, and in cancer therapy.