Scientists have made a significant breakthrough in understanding the axolotl's remarkable ability to regenerate limbs. Researchers at the Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA) have identified the Hand2 gene as a crucial regulator in this process. The study, published in *Nature* on May 21, 2025, elucidates the molecular framework underpinning the axolotl's positional memory during limb regeneration.
The research reveals that Hand2 activates the Shh signaling pathway, guiding cells to rebuild limbs accurately. This mechanism is described as a 'radio broadcast' model, where cells remember their position during regeneration. Upon injury, cells on the posterior side of the limb increase Hand2 expression, triggering Shh, which then instructs cells on where and what to regrow.
Notably, human homologs of Hand2 and Shh exist and function in limb development, suggesting the potential for translating the axolotl's regenerative abilities to humans. Scientists speculate that manipulating Hand2 could initiate limb formation. This discovery marks a transformative advance for regenerative medicine, offering insights into tissue engineering and potential therapies for limb regeneration in humans.