title: Influence of olfactory epithelium on mitral/tufted cell dendritic outgrowth.
abstract: Stereotypical connections between olfactory sensory neuron axons and mitral cell dendrites in the olfactory bulb establish the first synaptic relay for olfactory perception. While mechanisms of olfactory sensory axon targeting are reported, molecular regulation of mitral cell dendritic growth and refinement are unclear. During embryonic development, mitral cell dendritic distribution overlaps with olfactory sensory axon terminals in the olfactory bulb. In this study, we investigate whether olfactory sensory neurons in the olfactory epithelium influence mitral cell dendritic outgrowth in vitro. We report a soluble trophic activity in the olfactory epithelium conditioned medium which promotes mitral/tufted cell neurite outgrowth. While the trophic activity is present in both embryonic and postnatal olfactory epithelia, only embryonic but not postnatal mitral/tufted cells respond to this activity. We show that BMP2, 5 and 7 promote mitral/tufted cells neurite outgrowth. However, the BMP antagonist, Noggin, fails to neutralize the olfactory epithelium derived neurite growth promoting activity. We provide evidence that olfactory epithelium derived activity is a protein factor with molecular weight between 50-100 kD. We also observed that Follistatin can effectively neutralize the olfactory epithelium derived activity, suggesting that TGF-beta family proteins are involved to promote mitral/tufted dendritic elaboration.
authors.affiliation: Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, United States of America.
authors.forename: Ha
authors.initials: H
authors.lastname: Tran
authors.forename: Huaiyang
authors.initials: H
authors.lastname: Chen
authors.forename: Andreas
authors.initials: A
authors.lastname: Walz
authors.forename: Jamie C
authors.initials: JC
authors.lastname: Posthumus
authors.forename: Qizhi
authors.initials: Q
authors.lastname: Gong
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000502:physiology; D002450:Cell Communication; D003712:Dendrites / Q000648:ultrastructure*; D038681:Follistatin / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D009830:Olfactory Bulb / Q000166:cytology*; D009831:Olfactory Mucosa / Q000502:physiology*; D018034:Olfactory Receptor Neurons / Q000502:physiology*; D016212:Transforming Growth Factor beta
chemical_list: D019485:Bone Morphogenetic Proteins; D038681:Follistatin; D016212:Transforming Growth Factor beta