Wnt/β-catenin Signaling Regulates Regeneration in Diverse Tissues of the Zebrafish

Thesis (Ph.D.)--University of Washington, 2016-06

The ability to regenerate tissue after injury is limited by species, tissue type, and age of the organism. Understanding the mechanisms of endogenous regeneration provides greater insight into this remarkable biological process while also offering up potential therapeutic targets for promoting regeneration in humans. The Wnt/β-catenin signaling pathway has been implicated in zebrafish regeneration, including the fin and nervous system. The body of work presented here expands upon the role of Wnt/β-catenin signaling in regeneration, characterizing roles for Wnt/β-catenin signaling in multiple tissues. We show that cholinergic signaling is required for blastema formation and Wnt/β-catenin signaling initiation in the caudal fin, and that overexpression of Wnt/β-catenin ligand is sufficient to rescue blastema formation in fins lacking cholinergic activity. Next, we characterized the glial response to Wnt/β-catenin signaling after spinal cord injury, demonstrating that Wnt/β-catenin signaling is necessary for recovery of motor function and the formation of bipolar glia after spinal cord injury. Lastly, we defined a role for Wnt/β-catenin signaling in heart regeneration, showing that cardiomyocyte proliferation is regulated by Wnt/β-catenin signaling. These data demonstrate a conserved role for Wnt/β-catenin signaling in promoting regeneration across multiple tissue types in the zebrafish, and further show conservation of some of these functions in human tissue.