Identifying the Signaling Molecules Involved in the Early Stage of Epimorphic Regeneration Using Zebrafish (Larva) Tail as a Model System

The mechanism of the epimorphic regeneration of zebrafish tail is unknown. By fully understanding the molecular and cellular basis of the epimorphic regeneration mechanism of the zebrafish tail, it is possible to reverse-engineer it to develop therapies that can be used in mammals or even humans to reduce fibrosis, local inflammation & scar formation, and promote wound healing and regeneration. These therapies may then be utilized in unexpected ways and to varying degrees to facilitate treating a variety of chronic diseases. In the current study, in order to identify the signaling molecules involved in the notochord bead formation that happens in the early stage of zebrafish (larva) tail regeneration, chemical screening was carried out. Pharmacological treatments using either inhibitors or scavengers to down-regulate the candidate signaling molecules with the intention of intervening in the zebrafish (larva) tail regeneration process were performed, and the outcomes of these small molecule chemical treatments on either notochord bead formation or amputation-induced Ca2+ level or H2O2 level or SFK activity were assessed. After testing more than 30 chemicals, I found out that Ca2+, H2O2, SFK, CREB, EGFR, MAPKK, microtubule, MMP, PDE, PI3K, PKA, PKB & PKC are involved in the early stage (i.e., prior to blastema formation) of zebrafish tail regeneration, which can be broken down into 3 parts: (1) H2O2, SFK, EGFR, MMP, PDE, PI3K, PKA & microtubule participate in the notochord bead formation; (2) H2O2 & SFK promote Ca2+ signaling; (3) Ca2+, MAPKK, PKB, PKC & CREB up-regulate H2O2 signaling. In conclusion, I identified a few signaling molecules that might play a role in the early stage of zebrafish tail regeneration. Further investigation is needed to fully elucidate the interaction and signaling transduction networks between these molecules.