Abstract
Abstract: :
Purpose: The Wnt signaling pathway has critical roles in embryonic development. Wnt genes regulate stability of beta-catenin by controlling the activation of GSK-3. Several factor, as FGF, IGF, or BMP, has been implicated in lens fiber cell differentiation. Wnt and FGF signaling cooperatively participate in the development process of the many tissue. The previous studies also suggested for fiber differentiation that still unknown factors. In the present study, we examined whether Wnt signaling play important roles in lens fiber differentiation. Methods: We tested in lens epithelial cells, whether Wnt proteins could stimulate lens cell elongation. For these experiments, Wnt conditioned medium (CM) was prepared by each overexpression stable cell line. To confirm that the Wnt-induced elongation of cells was accompanied with fiber differentiation, we investigated for changes in the expression of lens fiber protein. Results: In an in vitro lens cell culture system, in which Wnt CM have not significant induce fiber differentiation, but Wnt stimulates rat lens epithelial cells to elongate into fiber-like cells after FGF-initiated differentiation. The lens fiber proteins, which accompanies fiber differentiation, were expressed in the elongated cells. Surprisingly, upregulation of proliferation and beta-crystallin expression by wnt dose not require initiation of FGF. Conclusions: These results suggest that differentiation in the rat lens is likely to be initiated by FGF signaling and fiber differentiation was enhanced by Wnt signaling. Our findings provide the first insights into the role of the Wnt signaling on lens epithelial-fiber differentiation.
Keywords: visual development • growth factors/growth factor receptors • signal transduction