Design and Biological Evaluation of hBest1-Containing Bilayer Nanostructures

Bestrophinopathies are a group of inherited retinal diseases caused by mutations in the BEST1 gene. The protein encoded by this gene, bestorphin-1 (hBest1), is a calcium-dependent transmembrane channel localized on the basolateral membrane of retinal pigment epithelial (RPE) cells. We have already demonstrated the surface behavior and organization of recombinant hBest1 and its interactions with membrane lipids such as 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), sphingomyelin (SM) and cholesterol (Chol) in models of biological membranes, which affect the hBest1 structure-function relationship. The main aim of our current investigation is to integrate pure hBest1 protein into lipid bilayer nanostructures. We synthesized and characterized various hBest1-containing nanostructures based on 1,2-Dipalmitoylphosphatidylcholine (DPPC), SM, glycerol monooleate (GMO) and Chol in different ratios and determined their cytotoxicity and incorporation into cell membranes and/or cells by immunofluorescence staining. Our results show that these newly designed nanoparticles are not cytotoxic and that their incorporation into MDCK II cell membranes (used as a model system) may provide a mechanism that could be applied to RPE cells expressing mutated hBest1 in order to restore their ion transport functions, affected by mutated and malfunctioning hBest1 molecules.