Researchers Use Advanced Techniques to Understand Limb Regeneration
Striving to identify the mechanisms of appendage regeneration, a research team led by Jessica L. Whited, PhD, at the Brigham and Women’s Hospital (BWH) Regenerative Medicine Center is using innovative molecular biology techniques to study limb regeneration in a colony of axolotl salamanders. By manipulating gene expression at specific points in time during limb regeneration, they are working to determine events that initiate the regenerative process.
“Humans and other mammals have extremely limited regenerative capacity in many key areas, including limbs,” said Dr. Whited. “Axolotl salamanders exhibit remarkable regenerative abilities and are genetically similar to humans with limbs that are anatomically similar to human limbs as well. By understanding how limb regeneration occurs in these animals, we hope to provide critical information for designing therapies to stimulate regeneration in humans.”
Analyzing Gene Expression
Dr. Whited and her team employ advanced sequencing technology to compare the gene expression in regenerated limbs, uninjured limbs, and the blastema – a collection of relatively dedifferentiated cells and stem cells that forms at the site of injury. Analysis is performed at both the tissue and single-cell level. Dr. Whited has developed a unique method for obtaining temporal control over exogenous gene expression (Proc Natl Acad Sci U S A. 2012 Aug 21;109(34):13662-7.). This inducible system allows for systematic analysis of phenotypes at defined developmental or regenerative time points. Methods to highly express genes of interest include viral gene transfer via pseudotyped retroviruses in axolotl cells (Development. Mar 1, 2013; 140(5): 1137-1146.) for both lineage and functional analyses in regenerating limbs.
Broad Implications of Research Findings
Salamanders not only regenerate limbs, but also can regenerate heart, brain, spine, and other tissue. Findings from the team’s research related to the healing process in salamanders may help the advancement of a wide range of regenerative research efforts.
“We know, for example, that healing in salamanders does not involve the formation of scar tissue, so scar-free healing is a key part of the regenerative process,” said Dr. Whited. “Understanding healing in these animals can ultimately have benefits for many other areas of research.”
Jessica L. Whited, PhD Regenerative Medicine Center, Brigham and Women’s Hospital