Regeneration of body part occurs in many, but not all, animals in Nature. Why some
animals can regenerate and others cannot is an important question in biology, and
may eventually be applicable to human medicine. The Tanaka laboratory has
investigated the regenerative capabilities of the axolotl salamander and defined the
regenerative cells, and injury signals that cause adult cells to become stem cells.
With the support of the Wittgenstein award, the Tanaka laboratory will investigate
how adult cells turn into stem cells and apply this knowledge investigate what is
different about mammalian cells that prevents regeneration. They will also
investigate how nerve cells find their correct connections during limb regeneration
and what happens if regeneration is unsuccessful and nerves do not find their
correct target. Reinnervation of muscle is the process by which nerves damaged due
to injury, find their way back to their muscle fiber targets. The process of muscle
reinnervation is not optimal in mammals with dire lifetime consequences for those
suffering from imprecise motor neuron growth after injury. The innovative
experiments proposed here elucidate how motor neurons successfully reinnervate
their original targets post-injury in the axolotl, a salamander whose limbs are
comparable to humans yet show powerful regenerative abilities and is now highly
accessible to transgenesis, live imaging, and cell transplantation allowing us to
eventually develop effective methods of reinnervation during nerve surgery with the
aspiration of a fully functional and complete recovery.