S100B expression defines a state in which GFAP-expressing cells lose their neural stem cell potential and acquire a more mature developmental stage.
During the postnatal development, astrocytic cells in the neocortex progressively lose their neural stem cell (NSC) potential, whereas this peculiar attribute is preserved in the adult subventricular zone (SVZ). To understand this fundamental difference, many reports suggest that adult subventricular GFAP-expressing cells might be maintained in immature developmental stage. Here, we show that S100B, a marker of glial cells, is absent from GFAP-expressing cells of the SVZ and that its onset of expression characterizes a terminal maturation stage of cortical astrocytic cells. Nevertheless, when cultured in vitro, SVZ astrocytic cells developed as S100B expressing cells, as do cortical astrocytic cells, suggesting that SVZ microenvironment represses S100B expression. Using transgenic s100b-EGFP cells, we then demonstrated that S100B expression coincides with the loss of neurosphere forming abilities of GFAP expressing cells. By doing grafting experiments with cells derived from beta-actin-GFP mice, we next found that S100B expression in astrocytic cells is repressed in the SVZ, but not in the striatal parenchyma. Furthermore, we showed that treatment with epidermal growth factor represses S100B expression in GFAP-expressing cells in vitro as well as in vivo. Altogether, our results indicate that the S100B expression defines a late developmental stage after which GFAP-expressing cells lose their NSC potential and suggest that S100B expression is repressed by adult SVZ microenvironment.
Raponi
Eric
E
INSERM, EMI 01-04, Grenoble, France.
Agenes
Fabien
F
Delphin
Christian
C
Assard
Nicole
N
Baudier
Jacques
J
Legraverend
Catherine
C
Deloulme
Jean-Christophe
JC
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D019070:Cell Lineage / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003342:Corpus Striatum / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009414:Nerve Growth Factors / Q000378:metabolism*; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism*; D018874:Spheroids, Cellular; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579159:S100b protein, mouse; D049452:Green Fluorescent Proteins; D004815:Epidermal Growth Factor