Sonic hedgehog is a polarized signal for motor neuron regeneration in adult zebrafish

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Michell M. Reimer - , University of Edinburgh (Author)
  • Veronika Kuscha - , University of Edinburgh (Author)
  • Cameron Wyatt - , University of Edinburgh (Author)
  • Inga Sörensen - , Leibniz University Hannover (LUH) (Author)
  • Rebecca E. Frank - , University of Edinburgh (Author)
  • Martin Knüwer - , University of Edinburgh (Author)
  • Thomas Becker - , University of Edinburgh (Author)
  • Catherina G. Becker - , University of Edinburgh (Author)

Abstract

In contrast to mammals, the spinal cord of adult zebrafish has the capacity to reinitiate generation of motor neurons after a lesion. Here we show that genes involved in motor neuron development, i.e., the ventral morphogen sonic hedgehog a (shha), as well as the transcription factors nkx6.1 and pax6, together with a Tg(olig2:egfp) transgene, are expressed in the unlesioned spinal cord of adult zebrafish. Expression is found in ependymoradial glial cells lining the central canal in ventrodorsal positions that match expression domains of these genes in the developing neural tube. Specifically, Tg(olig2:egfp) + ependymoradial glial cells, the adult motor neuron progenitors (pMNs), coexpress Nkx6.1 and Pax6, thus defining an adult pMN-like zone. shha is expressed in distinct ventral ependymoradial glial cells. After a lesion, expression of all these genes is strongly increased, while relative spatial expression domains are maintained. In addition, expression of the hedgehog (hh) receptors patched1 and smoothened becomes detectable in ependymoradial glial cells including those of the pMN-like zone. Cyclopamine-induced knock down of hh signaling significantly reduces ventricular proliferation and motor neuron regeneration. Expression of indicator genes for the FGF and retinoic acid signaling pathways was also increased in the lesioned spinal cord. This suggests that a subclass of ependymoradial glial cells retain their identity as motor neuron progenitors into adulthood and are capable of reacting to a sonic hedgehog signal and potentially other developmental signals with motor neuron regeneration after a spinal lesion.

Details

Original languageEnglish
Pages (from-to)15073-15082
Number of pages10
JournalJournal of Neuroscience
Volume29
Issue number48
Publication statusPublished - 2 Dec 2009
Peer-reviewedYes
Externally publishedYes

External IDs

PubMed 19955358

Keywords

ASJC Scopus subject areas