IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The wnt/b-catenin signaling pathway regulates sox2 expression and neurogenesis during olfactory regeneration in xenopus tadpoles
Autor/es:
PAZ DA; POZZI, AG; FRONTERA, J.
Lugar:
Rio de Janeiro
Reunión:
Congreso; 9th Word Congress International Brain Research Organization; 2015
Institución organizadora:
IBRO
Resumen:
[AbstractID: 410] PÔSTERTHE WNT/B-CATENIN SIGNALING PATHWAY REGULATES SOX2EXPRESSION AND NEUROGENESIS DURING OLFACTORY REGENERATION IN XENOPUS TADPOLESDANTEAGUSTIN PAZ1; ANDREA GABRIELA POZZI1; JIMENA LAURAFRONTERA1. 1.DEPT BIODIVERSIDAD Y BIOLOGÍA EXPERIMENTAL. UBA. AND IFIBYNE-CONICET,BUENOS AIRES - ARGENTINA. Keywords: StemCells;Neurogenesis;Olfactory Abstract Theolfactory epithelium (OE) is a pseudostratified epithelium composed ofolfactory receptor neurons (ORNs), sustentacular (SUS) cells and basal cells(BCs). The ability of the OE to regenerate after injury is mediated by at leasttwo populations of presumed stem cells: globose (GBCs) and horizontal basalcells (HBCs). Of these two populations of neural stem cells, GBCs aremoleculary and phenotipically analogous to the olfactory progenitors of theembryonic placode. In contrast, HBCs are a reserve stem cell population thatappears later in development and requires activation by severe epithelialdamage before contributing the epithelial reconstitution. Neither HBC emergencenor the mechanism of activation after injury are well understood.Our work has focused on the analysis of the factors and mechanisms involved inhomeostasis and neural regenerative capacity of the Xenopus laevis tadpoles OE.We studied the regeneration dynamics of the different cell types after chemicalinjury of the OE, and the implication of the transcription factor Sox2 and itsregulation through the Wnt signaling pathways. Our results demonstrate Sox2expression in proliferating basal cells found near to the basement membrane,some of which were identified as immature neurons expressing GAP43. Thissuggests that neural progenitors in the basal layer of the OE express thetranscription factor Sox2, and the expression of this protein is maintaineduntil the early stages of neuronal differentiation.During regeneration of the OE after chemical destruction by Zinc sulphatetreatment, we have determined an increase of gene expression of Sox2 and increasedSox2 positive (Sox2+) basal cells with proliferative potential thereforesuggest that basal cells are Sox2 expressing neural progenitors and wouldcontribute to the replenishment of olfactory cells.To evaluate the implication of the Wnt signaling pathway in regulation of Sox2expression, inhibition of Wnt / β-catenin pathway was induced byNorcantharidin. Under the canonical Wnt pathway inhibition, we observed amarked decrease in the Sox2 gene expression as well as the number of Sox2+basal cells during regeneration. However, no direct effect on Sox2 was observedunder normal conditions. These results suggest that Wnt / β-catenin signalingpathway would be involved in the regulation of Sox2 expression mainly undermassive regeneration conditions.Taken together, our results indicate that activation of the Wnt / β-cateninsignaling pathway is required for Sox2 expression in olfactory neuralprecursors after a massive destruction of the OE. This pathway may be relatedwith the HBCs activation. However, under normal physiological conditions, otherfactors would be involved and responsible for the regulation of Sox2 in basalcells.