BASIC FIBROBLAST GROWTH-FACTOR (FGF-2) INDUCED TRANSDIFFERENTIATION OF RETINAL-PIGMENT EPITHELIUM - GENERATION OF RETINAL NEURONS AND GLIA

In the present study we report that basic fibroblast growth factor (bF GF, FGF-2) promotes the transdifferentiation of Xenopus laevis larval retinal pigment epithelium (RPE) into neural retina, Using specific an tibodies we have examined the cellular composition of the regenerated retinal tissue, Our results show that, in addition to retinal neurons and photoreceptors, glial cells were also regenerated from the transdi fferentiated RPE, These results were specific to FGF-2, since other fa ctors that were tested, including acidic FGF (aFGF, FGF-1), epidermal growth factor (EGF), laminin, ECL, and Matrigel, exhibited no activity in inducing retinal regeneration, These results are the first in amph ibians demonstrating the functional role of FGF-2 in inducing RPE tran sdifferentiation. Transplantation studies were carried out to investig ate retinal regeneration from the RPE in an in vivo environment, Sheet s of RPE implanted into the lens-less eyes of larval hosts transformed into neurons and glial cells only when under the influence of host re tinal factors, In contrast, no retinal transdifferentiation occurred i f the RPE was implanted into the enucleated orbit. Taken together, the se results show that the amphibian RPE is capable of transdifferentiat ion into neuronal and glial cell-phenotypes and implicate FGF-2 as an important factor in inducing retinal regeneration in vitro. (C) 1997 W iley-Liss, Inc.