Synthetic lipid rafts formed by cholesterol nano-patch induce T cell activation

Abstract

AbstractLipid rafts are small and dynamic membrane compartments that are enriched with cholesterols or sphingolipids. The coalescence of small lipid rafts into a large lipid raft forms a signaling platform at the immunological synapse that plays a crucial role in controlling T cell activation. Cholesterol is a major component for the formation and function of lipid rafts, but the relationship between the spatial configuration of cholesterols and the lipid raft mediated membrane segregation as well as TCR signaling remains poorly understood. Here we used cholesterol conjugated DNA origami nanostructures, cholesterol nano-patch (CNP) to construct lipid rafts on intact live T cells. CNPs are two-dimensional DNA scaffolds that allow controlling the spatial presentation of cholesterols in the plasma membrane. CNPs efficiently bind onto the T cell membrane and rapidly induce large, polarized membrane cap structures which colocalize with flotillin-1. These CNP mediated membrane segregations, which we define as synthetic lipid rafts, drive membrane segregation of key signaling molecules including TCR and CD45, thereby triggering downstream TCR signaling and subsequently functional T cell responses without antigenic challenges. Our work highlights the potential of CNP in uncovering the mechanisms that lipid rafts induced by cholesterols drive membrane protein reorganization and control T cell signaling, and offers valuable insights into the design of antigen-independent immunotherapies.