INTEGRIN EXPRESSION IN THE DEVELOPING MOUSE RETINA. 388

Purpose: The goal of this study was to define the repertoire of integrin expression in the developing mouse retina, particularly vascular expression. Methods: Eyes from 17-21 day old C57BL mice were removed and embedded in OCT and frozen at -70°C. 12 μm sections were prepared and were successively incubated for 1 hour each as follows: PBS with 3%BSA, rat anti-mouse integrin or laminin monoclonal antibody or hamster anti-mouse α_v, Texas-Red conjugated secondary antibody or FITC-conjugated for α_v, and FITC-conjugated RCA-I lectin. Incubations included appropriate washings with PBS between steps. Double staining with the FITC-conjugated RCA-I lectin was performed for all of the above primary antibodies with the exception of that for α_v. Sections were examined by fluorescent microscopy. Results: The expression of laminin in intraretinal vessels was demonstrated by the colocalization of RCA-I, which labels mouse vasculature, and laminin staining.α₆ and β₁ integrin subunits, which form the laminin receptor α₆β₁, also localized to intraretinal vessels. α₆ staining was also seen in cells of the inner nuclear cell layer. The retinal vasculature had minimal β₄ staining and lacked α₂, α₃, α₅, and α_v staining. α₃ staining was seen in the outer synaptic layer.Conclusion: Intraretinal vessels in the developing mouse retina express laminin and the integrin laminin receptorsα₆β₁ and minimally α₆β₄. No vascular staining for the integrin subunits α₂, α₃,α₅, or α_v were demonstrated.

(Supported NIH grant EY00330)