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L Geng, L Del Priore; Pre-transplant Exposure to Extracellular Matrix (ECM) Ligands Alters Integrin Expression of RPE Surface . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3443.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: RPE transplanted into the subretinal space must attach to Bruch's membrane (BM) to survive, and RPE-BM interactions are mediated partially by integrin receptors on the RPE surface. We determined whether exposing RPE to different ECM ligands prior to transplantation modulates the expression of integrin subunits on the RPE surface, with the goal of enhancing RPE-substrate interaction during transplant surgery. Methods: First passage confluent human RPE were harvested from tissue culture and seeded onto dishes coated with known ECM components (4µg/cm2 laminin, 4µg/cm2 vitronectin, 10µg/cm2 fibronectin, and 10µg/cm2 collagen IV). 24 hours after seeding RPE were harvested by trypsinization and plated into 96 well tissue culture plates overnight. Mouse antibodies to specific human integrin subunits were used as a primary antibody and alkaline-conjugated goat anti-mouse IgG used as a second antibody after non-specific binding was blocked with goat serum. The absorbance at 405 nm was used to determine the expression of RPE integrin receptor subunits per cell. Results: Seeding onto dishes precoated with a mixture of ECM ligands significantly increased the amount of ß1, ß2, ß3, ß4, α5, α2ß1 and α5ß1 in human RPE. Exposure to vitronectin alone increased the amount of ß1, ß3 and ß4. Exposure to collagen IV alone increased the expression of ß2. ß4 was increased by exposure to either fibronectin, collagen IV, vitronectin or to the mixture. Conclusion: The expression of integrin subunits on the RPE can be up regulated or down regulated by pre-transplant exposure of the RPE to known ECM ligands. This strategy may be useful to increase the ability of RPE harvested for transplantation to attach to BM and ultimately repopulate this surface.
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