RESUMEN
During embryo neurogenesis, neurons that originate from stem cells located in the forebrain subventricular zone (SVZ) continuously migrate to the olfactory bulb (OB). However, other authors describe the occurrence of resident stem cells in the OB. In the present work we report that the absence of tumor suppressor protein p53 increases the number of neurosphere-forming cells and the proliferation of stem cells derived from 13.5-day embryo OB. Interestingly, differentiation of p53 knockout-derived neurospheres was biased toward neuronal precursors, suggesting a role for p53 in the differentiation process. Moreover, we demonstrate the relevance of p53 in maintaining chromosomal stability in response to genotoxic insult. Finally, our data show that neurosphere stem cells are highly resistant to long-term epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) deprivation in a p53-independent fashion, and they preserve their differentiation potential. Thus, these data demonstrate that p53 controls the proliferation, chromosomal stability and differentiation pattern of embryonic mouse olfactory bulb stem cells.
Asunto(s)
Diferenciación Celular/genética , Neurogénesis/genética , Neuronas/fisiología , Células Madre/fisiología , Proteína p53 Supresora de Tumor/fisiología , Animales , Anexinas/metabolismo , Ciclo Celular/genética , Proliferación Celular/efectos de los fármacos , Proliferación Celular/efectos de la radiación , Células Cultivadas , Aberraciones Cromosómicas/efectos de la radiación , Embrión de Mamíferos , Factor de Crecimiento Epidérmico/deficiencia , Factor 2 de Crecimiento de Fibroblastos/deficiencia , Citometría de Flujo/métodos , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Regulación del Desarrollo de la Expresión Génica/genética , Proteína Ácida Fibrilar de la Glía/metabolismo , Etiquetado Corte-Fin in Situ/métodos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neurogénesis/efectos de los fármacos , Neuronas/efectos de los fármacos , Neuronas/efectos de la radiación , Antígenos O/metabolismo , Bulbo Olfatorio/citología , Unión Proteica , Factores de Tiempo , Tubulina (Proteína)/metabolismo , Proteína p53 Supresora de Tumor/deficiencia , Rayos X/efectos adversosRESUMEN
Two monoclonal antibodies (Nilo1 and Nilo2) were generated after immunization of hamsters with E13.5 olfactory bulb-derived mouse neurospheres. They are highly specific for neural stem and early progenitor cell surface antigens. Nilo positive cells present in the adult mouse subventricular zone (SVZ) were able to initiate primary neural stem cell cultures. Moreover, these antibodies added to neurosphere cultures induced proliferation arrest and interfered with their differentiation. In the lateral ventricles of adult mice, Nilo1 stained a cell subpopulation lining the ventricle and cells located in the SVZ, whereas Nilo2 stained a small population associated with the anterior horn of the SVZ at the beginning of the rostral migratory stream. Co-staining of Nilo1 or Nilo2 and neural markers demonstrated that Nilo1 identifies an early neural precursor subpopulation, whereas Nilo2 detects more differentiated neural progenitors. Thus, these antibodies identify distinct neurogenic populations within the SVZ of the lateral ventricle.