Host cellular cholesterol distribution and dynamics during enteroviral infection

Many RNA viruses, including enteroviruses, remodel host ER membranes to form platforms with unique lipid components to assemble replication complexes and synthesize new viral RNA. Cholesterol is a critical component of cellular membranes regulating fluidity and being indispensable for proper assembly and function of membrane based protein-lipid complexes. Here we show that enteroviruses harness the clathrin mediated endocytosis (CME) pathway to transfer free cholesterol from the plasma membrane to the viral replication organelles (VROs). We show that cholesterol is responsible for regulating viral protein processing and facilitates viral RNA synthesis, and disrupting CME causes cellular cholesterol pools to be stored in lipid droplets obstructing the transfer to VROs and inhibiting viral replication. In contrast, we found that the presence of excess intracellular cholesterol, as in cells lacking caveolins or those from patients with Niemann-Pick disease, stimulates viral replication. We demonstrate that, the redistribution of free cellular cholesterol and the cellular recycle dynamics are affected during infection. The CME rate of uptake does not change during the initial 2 hours of infection while the rate of cellular endosomal recycling is inhibited resulting in a net decrease of free cholesterol at the plasma membrane, and facilitating the access and active transfer of cholesterol from enriched internal cellular compartments to VROs. Our findings indicate that cholesterol is critical for enteroviral replication and that CME has an important role in the enteroviral life cycle and in the host cellular cholesterol homeostasis.Ph.D.Includes bibliographical referencesby Marianita Santian