Characterization of TGFβ signaling during tail regeneration in the leopard Gecko (Eublepharis macularius)

Abstract

Introduction: The transforming growth factor beta (TGFβ)/activin signaling pathway has a number of documented roles during wound healing and is increasingly appreciated as an essential component of multi-tissue regeneration that occurs in amphibians and fish. Among amniotes (reptiles and mammals), less is known due in part to the lack of an appropriate model organism capable of multi-tissue regeneration. The leopard gecko Eublepharis macularius is able to spontaneously, and repeatedly, regenerate its tail following tail loss. We examined the expression and localization of several key components of the TGFβ/activin signaling pathway during tail regeneration of the leopard gecko. Results: We observed a marked increase in phosphorylated Smad2 expression within the regenerate blastema indicating active TGFβ/activin signaling. Interestingly, during early regeneration, TGFβ1 expression is limited whereas activin-βA is strongly upregulated. We also observe the expression of EMT transcription factors Snail1 and Snail2 in the blastema. Conclusions: Combined, these observations provide strong support for the importance of different TGFβ ligands during multi-tissue regeneration and the potential role of TGFβ/activin-induced EMT programs during this process. Developmental Dynamics 242:886-896, 2013. © 2013 Wiley Periodicals, Inc. Key Findings: Large induction of phosphorylated SMAD2 in blastema cells indicates robust activation of TGFβ/activin pathway during regeneration. TGFβ1 expression absent in early regenerate tissue and activin-βA mRNA significantly upregulated in regenerate tissue suggestive of dynamic ligand expression patterns. EMT transcription factors Snail1 and Snail2 significantly upregulated in regenerating tissue. © 2013 Wiley Periodicals, Inc.