title: Proteomic analysis of astrocytic secretion in the mouse. Comparison with the cerebrospinal fluid proteome.
abstract: Astrocytes, the most abundant cell type in the central nervous system, are intimately associated with synapses. They play a pivotal role in neuronal survival and the brain inflammatory response. Some astrocytic functions are mediated by the secretion of polypeptides. Using a proteomic approach, we have identified more than 30 proteins released by cultured astrocytes. These include proteases and protease inhibitors, carrier proteins, and antioxidant proteins. Exposing astrocytes to brefeldin A, which selectively blocks secretory vesicle assembly, suppressed the release of some of these proteins. This indicates that astrocytes secrete these proteins by a classic vesicular mechanism and others by an alternative pathway. Astrocytes isolated from different brain regions secreted a similar pattern of proteins. However, the secretion of some of them, including metalloproteinase inhibitors and apolipoprotein E, was region-specific. In addition, pro-inflammatory treatments modified the profile of astrocytic protein secretion. Finally, more than two thirds of the proteins identified in the astrocyte-conditioned medium were detectable in the mouse cerebrospinal fluid, suggesting that astrocytes contribute to the cerebrospinal fluid protein content. In conclusion, this study provides the first unbiased characterization of the major proteins released by astrocytes, which may play a crucial role in the modulation of neuronal survival and function.
authors.affiliation: Unité Propre CNRS 2580, 141 rue de la Cardonille, 34094 Montpellier cedex 5, France.
authors.forename: Mireille
authors.initials: M
authors.lastname: Lafon-Cazal
authors.forename: Oumeya
authors.initials: O
authors.lastname: Adjali
authors.forename: Nathalie
authors.initials: N
authors.lastname: Galéotti
authors.forename: Joël
authors.initials: J
authors.lastname: Poncet
authors.forename: Patrick
authors.initials: P
authors.lastname: Jouin
authors.forename: Vincent
authors.initials: V
authors.lastname: Homburger
authors.forename: Joël
authors.initials: J
authors.lastname: Bockaert
authors.forename: Philippe
authors.initials: P
authors.lastname: Marin
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002478:Cells, Cultured; D002555:Cerebrospinal Fluid / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000378:metabolism; D020543:Proteome; D040901:Proteomics
chemical_list: D009419:Nerve Tissue Proteins; D020543:Proteome