Spatial Distribution of Fibroblast Growth Factor Receptor 2 in Normal and Lesioned Central Nervous System of Pleurodeles waltlii

Abstract

Fibroblast Growth Factors (FGFs) have been implicated in numerous cellular processes including proliferation, migration, differentiation and neuronal survival. One of these growth factors, Fibroblast Growth Factor 2 (FGF2), is apparently implicated in the ability of the adult salamander (Pleurodeles waltlii) to recover locomotion following complete transection of the spinal cord. In a previous study, we reported up regulation of FGF2 during regeneration of damaged axons and recovery of hind limb locomotion. In this study reported here, we investigated the spatial distribution of FGFR2-one of the receptors that mediate the effects of FGF2-using a variety of techniques, namely, western blot, immunohistochemistry and in situ hybridization. We find that in intact animals FGFR2 is mainly expressed in the most posterior part of body Spinal Cord (SC3) specifically in neurons. However, lesioning the spinal cord produces increased expression in Brainstem (BS) neurons and decreased expression in posterior parts of the spinal cord not only in neurons but also in the neuroglial ependymal cells lining the central canal. This suggests that FGF2 simultaneously activates FGFR1 and 2, perhaps at different points in the regeneration process and thus FGFR2 might play at least an indirect role in the spontaneous regeneration observed in this species and might be relevant to the treatment of spinal cord lesions in humans. Verification of this possibility will require studies of additional time points.