Engineered Nanolipoproteins as Biosynthetic Decoys for Pathogen-Binding

Abstract

The ability to exogenously present cell-surface receptors in a synthetic system offers an opportunity to provide host cells with protection from pathogenic toxins. Practical implementations suffer from serious limitations, primarily because of difficulties in mimicking the role of the membrane micro-environment during the complex and dynamic pathogen-receptor interaction. To this end, we have developed reconstituted lipoprotein - nanometer-sized discoidal lipid bilayers of arbitrary composition bounded by apolipoprotein - to serve as a versatile, biocompatible and stable platform to house pathogen-binding receptors in a membrane-like environment. Our approach exploits the notion that a control of biophysical properties of the membrane micro-environment allows to modulate interactions between membrane-embedded receptors and their pathogenic (e.g., bacterial toxin) targets. We demonstrate here, using a Foerster Resonance Energy Transfer (FRET) based assay, that ganglioside GM1 receptors incorporated at controlled concentrations in reconstituted lipoprotein bind cholera toxin with greater affinity than liposome-based systems. Furthermore, fluorescence microscopy investigations of cholera toxin presented to populations of mammalian cells show that GM1-laden lipoprotein can function as decoys without harming healthy cells.