Lipid Specificity of the Fusion of Bacterial Extracellular Vesicles with the Host Membrane

Abstract

Bacterial membrane vesicles (MVs) facilitate long-distance delivery of virulence factors crucial for pathogenicity. The entry and trafficking mechanisms of virulence factors inside host cells is recently emerging, however, if bacterial MVs modulate the physicochemical properties of the host lipid membrane remains unknown. Here we quantitatively show that bacterial MV interaction increases the fluidity, dipole potential and elasticity of a biologically relevant multi-component host model membrane. The presence of lipids containing head-groups such as phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol and a moderate acyl chain length of C16 helps the MV interaction. While significant binding of bacterial MVs to the raft-like lipid membranes with phase separated regions of the membrane was observed, however, the elevated levels of cholesterol tend to hinder the interaction of bacterial MVs. We further quantify the change in excess Gibbs free energy of mixing of bacterial MVs with host lipid membranes driving the modulation of host membrane parameters.