title: Proliferation, migration and differentiation of ependymal region neural progenitor cells in the brainstem after hypoglossal nerve avulsion.
abstract: OBJECTIVE
  Cells in the ependymal region in the adult central nervous system (CNS) have been found to possess neural progenitor cell (NPC) like features including capacity for generating new neurons and glia in response to injury and inflammatory disease. Whether these cells are activated after a peripheral nerve injury has not previously been extensively evaluated.
  
  
  METHODS
  We investigate the possible activation and effect of NPCs in the ependymal region in the immediate vicinity to the hypoglossal nucleus in the brainstem using two models of injuries, hypoglossal nerve transection and nerve avulsion after which the proliferation, migration and differentiation of ependymal regional NPCs were evaluated.
  
  
  RESULTS
  We showed that: (i) immunoreactivity for Sox2 was detected in cells in the ependymal region of the brainstem and that BrdU/Sox2-positive cells were observed after avulsion, but not after transection injury; (ii) avulsion induces re-expression of nestin in the ependymal layer as well as induced NPC migration from the ependymal layer; (iii) the chemokine SDF-1α (a marker for migrating cells) was upregulated ipsilateral to the nerve injury; (iiii) the NPCs migrating differentiated only into GFAP-positive astrocytes in the hypoglossal nucleus.
  
  
  CONCLUSIONS
  These results suggest that nerve avulsion injury induces in parallel with the retrograde "axon reaction" activation of endogenous NPCs in the ependymal region and further suggest that these cells could be involved in repair and neuroregeneration after injury within the brainstem.
authors.affiliation: Department of Clinical Neuroscience, Department of Neurosurgery and Neurology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Michael
authors.initials: M
authors.lastname: Fagerlund
authors.forename: Nasren
authors.initials: N
authors.lastname: Jaff
authors.forename: Alexandre I
authors.initials: AI
authors.lastname: Danilov
authors.forename: Inti
authors.initials: I
authors.lastname: Peredo
authors.forename: Lou
authors.initials: L
authors.lastname: Brundin
authors.forename: Mikael
authors.initials: M
authors.lastname: Svensson
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000166:cytology / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation; D004805:Ependyma / Q000166:cytology / Q000502:physiology*; D005260:Female; D061228:Hypoglossal Nerve Injuries / Q000473:pathology* / Q000503:physiopathology; D009474:Neurons / Q000166:cytology* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*