Localization of glucocorticoid receptors in mice retina

JULIAN LK; TORBIDONI V; ZHANG X; IRIBARNE M; YORIO T; SUBURO AM

Buenos Aires

Congreso; XVII International Congress of Eye Research (ICER); 2006

Internationational Society of Eye Research

PURPOSE: Glucocorticoids have profound effects on cell differentiation, proliferation and death. These effects are mediated through the glucocorticoid-receptor protein, which is mainly considered a ligand dependent transcription factor. Glucocorticoids are essential to neuronal function; however, their excess after brain injury can be detrimental to neuronal survival. Since Glucocorticoids have an important role in ophthalmological treatments our aim is to explore the role of these hormones on survival of retinal cells. To understand this role, we have made an immunocytochemical analysis describing the cellular localization of Glucocorticoid Receptors (GRs) in the mouse retina. METHODS: We have used the polyclonal antibodies SC-1003 (Santa Cruz Biotechnology, Santa Cruz, CA) against an epitope mapping at the N-terminus of GR of human origin, and PA3-514 (Affinity Bioreagents), against the synthetic peptide N(728) V M W L K P E S T S H T L I(742) C. Specificity of these antibodies has been previously demonstrated (Zhang et al. 2005). Present tests were done in cryosections from BALB-C and C57BL/6J mice, using nickel-enhanced imunoenzymatic procedures for conventional light microscopy and immunofluorescence for confocal microscopy. RESULTS: The two antisera gave similar results. In retinal cryosections, they produced strong staining of cells in the ganglion cell layer (GCL) cells and weaker staining of nuclei in the inner nuclear layer (INL). Several strata of the inner plexiform layer (IPL) were also immunostained, showing the presence of GRs in synaptic processes. Strong punctate immunoreactivity was also observed in the outer plexiform layer (OPL), indicating that GRs would also be present in these synaptic processes. CONCLUSIONS: Nuclear localization of GRs is compatible with their well known role as transcription factors. However, their prominent presence in synaptic layers of the retina suggests that they may also have non-genomic effects, probably associated with synaptic transmission and plasticity.