Throughout human life, many cells such as hair follicles and certain tissues such as liver can be continuously replaced to maintain tissue integrity in response to normal, daily wear and tear. However, the human response to more serious tissue damage, such as acute damage to limbs or to the spinal cord, is limited to relatively simple wound healing, whereby collagenous scar tissue fills the injury site, assuring the tissue’s structural integrity but often resulting in a debilitating loss of functional activity. While humans do exhibit some very limited regenerative capacity (e.g. finger tips), other vertebrates exhibit sometimes astonishing regenerative ability. Salamanders show the highest diversity in being able to regenerate limbs, tail, heart, eyes and jaw
Our aim is to understand at the molecular and cellular level how an axolotl spinal cord can functionally repair after injury and why mammals cannot. To this end we have used transcriptional profiling to identify key differences at the miRNA level between axolotl and rat after spinal cord injury. In particular we are focusing on the differences between the rostral and caudal sides of the injury site and how the axolotl creates a permissive environment for axonal regrowth while mammals do not. We are focusing not just on the neuronal cells but also on the contribution and interaction of the other cells especially endothelial cells and skin to this repair process.
(For a comprehensive list of recent publications, refer to PubMed, a service provided by the National Library of Medicine.)
Erickson JR, Echeverri K. In vivo modulation and quantification of microRNAs during axolotl tail regeneration. Methods Mol Biol. 2015;1290:159-67.
Diaz Quiroz JF, Tsai E, Coyle M, Sehm T, Echeverri K. Precise control of miR-125b levels is required to create a regeneration-permissive environment after spinal cord injury: a cross-species comparison between salamander and rat. Dis Model Mech. 2014 Jun;7(6):601-11.
Diaz Quiroz JF, Echeverri K. Spinal cord regeneration: where fish, frogs and salamanders lead the way, can we follow? Biochem J. 2013 May 1;451(3):353-64.
Sehm T, Sachse, C , Frenzel, C and Echeverri K. miR-196 is an essential early-stage regulator of tail regeneration, upstream of key spinal cord patterning events. Dev Biol. 2009 Oct 15;334(2):468-80. Epub 2009 Aug 13
Echeverri, K and AC Oates. 2007.Suppressor of Hairless coordinates bilateral cyclic gene expression during somitogenesis and plays an important role in left-right patterning of the vertebrate embryo. Dev. Biol. Jan 15;301(2):388-403
Echeverri, K and EM Tanaka. 2005. Proximodistal Patterning during Limb Regeneration. Dev. Biol. 279(2):391-401.
Echeverri, K. and EM Tanaka. 2002. Ectoderm to Mesoderm Lineage Switching during Axolotl Tail Regeneration.Science 298: 1993-1996
Echeverri K, Tanaka EM. Mechanisms of muscle dedifferentiation during regeneration.Semin Cell Dev Biol. 2002 Oct;13(5):353-60. Review.
Echeverri, K., Clarke, JD and EM Tanaka. 2001. In vivo imaging indicates muscle fiber dedifferentiation is a major contributor to the regenerating tail blastema. Dev. Biol. 236 (1):151-64.