Activated Wnt Signaling Triggers Limb Regeneration

Researchers have shown that by activating the Wnt signaling pathway they could stimulate the regeneration of wing tissue in a developing chick embryo.

The Wnt signaling pathway is known to be critically involved in the process of limb regeneration in such diverse organisms as frogs, zebrafish, and salamanders. In the current study, investigators from the Salk Institute for Biological Studies (La Jolla, CA, USA) worked with developing chicken embryos. They administered either inhibitory or excitatory factors for Wnt signaling directly to the remaining bulge after they removed a limb from the experimental embryos. Results published in the November 17, 2006, online edition of Genes and Development revealed that activation of Wnt signaling stimulated cell division and regeneration of the missing limb.

"In this simple experiment, we removed part of the chick embryo's wing, activated Wnt signaling, and got the whole limb back--a beautiful and perfect wing,” said senior author Dr. Juan Carlos Izpisúa Belmonte, professor of genetics at the Salk Institute. "By changing the expression of a few genes, you can change the ability of a vertebrate to regenerate their limbs, rebuilding blood vessels, bone, muscles, and skin--everything that is needed.”

The investigators also learned that time played a key role in the regenerative process; too much exposure to activate Wnt signaling generated cancerous growth. Dr. Belmonte explained, "This has to be done in a controlled way, with just a few cells for a specific amount of time. The fact is that this pathway is involved in cell proliferation, whether it is to generate or regenerate limbs, control stem cells, or produce cancer.”



Related Links:
Salk Institute for Biological Studies