In vitro differentiation of chick spinal cord neurons in the presence of Reissner's fibre, an ependymal brain secretion.
The subcommissural organ (SCO), which belongs to the circumventricular organs, is a specialized ependymal structure of the brain that secretes glycoproteins into the cerebrospinal fluid (CSF) which condense to form a thread-like structure, the Reissner's fibre (RF). Regarding the presence of this ependymal brain secretion all along the central canal of the developing spinal cord, we analysed a putative developmental activity of RF on neuronal spinal cord cells. The effects of RF proper and soluble RF-material were examined in primary cultures of dissociated spinal cord cells from day 6 chicken embryos. In serum-containing mixed glial/neuronal cell cultures, both RF and soluble RF-material promoted neuronal survival. This effect was blocked by addition of specific antibodies raised against bovine RF into the culture medium. In serum-free neuron-enriched cultures, no neuronal survival activity was observed; however, under these conditions RF proper induced neuronal aggregation and neuritic outgrowth of spinal cord cells. Interestingly, neurites extending from the aggregates appeared mainly unfasciculated. Our results suggest a direct modulation of cell-cell interactions by SCO/RF glycoproteins and an indirect survival effect on neurons. These data strengthen the hypothesis of the involvement of SCO/RF complex in the development of the central nervous system (CNS) and are discussed regarding molecular features of SCO-spondin, a novel glycoprotein recently identified in this complex.
Monnerie
H
H
INSERUM U 384, Faculté de Médecine, Clermont-Ferrand, France.
Dastugue
B
B
Meiniel
A
A
D000818:Animals; D000918:Antibody Specificity; D002449:Cell Aggregation / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D002642:Chick Embryo; D016895:Culture Media, Serum-Free; D004805:Ependyma / Q000378:metabolism*; D006023:Glycoproteins / Q000134:cerebrospinal fluid / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000134:cerebrospinal fluid / Q000378:metabolism*; D009457:Neuroglia / Q000166:cytology; D009474:Neurons / Q000166:cytology; D012995:Solubility; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*
D016895:Culture Media, Serum-Free; D006023:Glycoproteins; D009419:Nerve Tissue Proteins