Glial cell line-derived neurotrophic factor promotes the survival of early postnatal spinal motor neurons in the lateral and medial motor columns in slice culture.
The mechanisms by which trophic factors bring about spinal motor neuron (MN) survival and regulate their number during development are not well understood. We have developed an organotypic slice culture model for the in vitro study of the trophic requirements and cell death pathways in MNs of postnatal day 1-2 mice. Both lateral motor column (LMC) and medial motor column (MMC) neurons died within 72 hr when grown in serum-free medium without trophic factors. Brain-derived neurotrophic factor, ciliary neurotrophic factor, and 8-(4-chlorophenylthio)-cAMP promoted the survival of a proportion of the neurons, but glial cell line-derived neurotrophic factor (GDNF) was the most effective trophic factor, supporting approximately 60% of MNs for 1 week in culture. Homozygous deficiency for bax, a proapoptotic member of the Bcl-2 family, saved the same proportion of neurons as GDNF, suggesting that GDNF alone was sufficient to maintain all "rescuable" MNs for at least 1 week. Analysis of MN survival in GFRalpha-1(-/-) mice demonstrated that the trophic effect of GDNF was completely mediated by its preferred coreceptor, GDNF family receptor alpha-1 (GFRalpha-1). None of the other GDNF family ligands supported significant MN survival, suggesting that there is little ligand-coreceptor cross talk within the slice preparation. Although MN subtypes can be clearly defined by both anatomical distribution and ontogenetic specification, the pattern of trophic factor responsiveness of neurons from the MMC was indistinguishable from that seen in the LMC. Thus, in contrast to all other factors and drugs studied to date, GDNF is likely to be a critical trophic agent for all early postnatal MN populations.
Rakowicz
Wojtek P
WP
Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Staples
Christopher S
CS
Milbrandt
Jeffrey
J
Brunstrom
Janice E
JE
Johnson
Eugene M
EM
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects* / Q000502:physiology; D020934:Ciliary Neurotrophic Factor / Q000494:pharmacology; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D029721:Drosophila Proteins; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006720:Homozygote; D066298:In Vitro Techniques; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009046:Motor Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000172:deficiency / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology; D051028:bcl-2-Associated X Protein
C494827:Bax protein, mouse; D019208:Brain-Derived Neurotrophic Factor; D020934:Ciliary Neurotrophic Factor; D016895:Culture Media, Serum-Free; D029721:Drosophila Proteins; C495040:Gdnf protein, mouse; C494988:Gfra1 protein, mouse; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D013873:Thionucleotides; D051028:bcl-2-Associated X Protein; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D000242:Cyclic AMP; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila