title: Schwann cells migrate along axons in the absence of GDNF signaling.
abstract: BACKGROUND
  During development neural crest derived Schwann Cell (SC) precursors migrate to nerve trunks and populate nascent nerves. Axonal ensheathment by SC is a prerequisite for normal nerve function and the integrity of myelinated as well as nonmyelinated axons. To provide adequate support functions, SC colonize entire nerves. One important prerequisite for this is their migration into distal axonal regions.
  
  
  RESULTS
  Here, we studied the role of Glial cell line derived neurotrophic factor (GDNF), a TGF-beta related growth factor, for SC migration. To this end we used a superior cervical ganglion (SCG) explant-SC migration assay, GDNF null mutant mouse embryos and a chemical inhibitor for GDNF signaling in combination with time-lapse imaging. We found that GDNF signaling is dispensable for SC migration along murine embryonic sympathetic axons. Furthermore, in vivo analyzes revealed that SC migration along the sciatic nerve is also not dependent on GDNF.
  
  
  CONCLUSIONS
  In contrast to previous in vitro findings in the sciatic nerve and a SC precursor cell line, our results clearly indicate that GDNF is dispensable for embryonic SC migration. This is demonstrated for the sympathetic nervous system and also for the sciatic nerve in mouse.
authors.affiliation: Department of Neuroanatomy, University of Heidelberg, Heidelberg, Germany. stephan.heermann@cos.uni-heidelberg.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Heermann
authors.forename: Björn
authors.initials: B
authors.lastname: Spittau
authors.forename: Katalin
authors.initials: K
authors.lastname: Zajzon
authors.forename: Markus H
authors.initials: MH
authors.lastname: Schwab
authors.forename: Kerstin
authors.initials: K
authors.lastname: Krieglstein
mesh_terms: D000818:Animals; D016590:Aphidicolin / Q000494:pharmacology; D001369:Axons / Q000187:drug effects / Q000502:physiology*; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D049109:Cell Proliferation / Q000187:drug effects; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000172:deficiency*; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation / Q000235:genetics; D020932:Nerve Growth Factor / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D009418:S100 Proteins / Q000378:metabolism; D012583:Schwann Cells / Q000187:drug effects / Q000502:physiology*; D012584:Sciatic Nerve / Q000166:cytology* / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics*; D017783:Superior Cervical Ganglion / Q000166:cytology; D013997:Time Factors; D059008:Time-Lapse Imaging; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; C494988:Gfra1 protein, mouse; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006657:Histones; D009418:S100 Proteins; D016590:Aphidicolin; D020932:Nerve Growth Factor; D014446:Tyrosine 3-Monooxygenase