Neurotrophic properties of olfactory ensheathing glia.
Olfactory ensheathing cells (OEC) constitute a specialized population of glia that accompany primary olfactory axons and have been reported to facilitate axonal regeneration after spinal cord injury in vivo. In the present report we describe OEC neurotrophic factor expression and neurotrophic properties of OECs in vitro. Investigation of the rat olfactory system during development and adulthood by radioactive in situ hybridization revealed positive labeling in the olfactory nerve layer for the neurotrophic molecules S-100beta, CNTF, BMP-7/OP-1, and artemin, as well as for the neurotrophic factor receptors RET and TrkC. Ribonuclease protection assay of cultured OEC revealed expression of NGF, BDNF, GDNF, and CNTF mRNA, while NT3 and NT4 mRNA were not detectable. In vitro bioassays of neurotrophic activity involved coculturing of adult OEC with embryonic chick ganglia and demonstrated increased neurite outgrowth from sympathetic, ciliary, and Remak's ganglia. However, when culturing the ganglia with OEC-conditioned medium, neurite outgrowth was not stimulated to any detectable extent. Our results suggest that the neurotrophic properties of OEC may involve secretion of neurotrophic molecules but that cellular interactions are crucial.
Lipson
Adam C
AC
Department of Neuroscience, Karolinska Institutet, S-171 77 Stockholm, Sweden.
Widenfalk
Johan
J
Lindqvist
Eva
E
Ebendal
Ted
T
Olson
Lars
L
D000818:Animals; D001681:Biological Assay; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D002642:Chick Embryo; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D029721:Drosophila Proteins; D005724:Ganglia / Q000166:cytology / Q000196:embryology; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D017403:In Situ Hybridization; D009414:Nerve Growth Factors / Q000096:biosynthesis* / Q000235:genetics; D016501:Neurites / Q000187:drug effects / Q000502:physiology; D009457:Neuroglia / Q000166:cytology* / Q000378:metabolism*; D023282:Nuclease Protection Assays; D009830:Olfactory Bulb / Q000166:cytology / Q000196:embryology; D009832:Olfactory Nerve / Q000166:cytology* / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D051096:Proto-Oncogene Proteins c-ret; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics; D020812:Receptor, trkC / Q000096:biosynthesis / Q000235:genetics
D017077:Culture Media, Conditioned; D029721:Drosophila Proteins; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D009414:Nerve Growth Factors; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; D020812:Receptor, trkC; C416649:Ret protein, Drosophila; C495001:Ret protein, rat