Cholesterol Depletion in Measles Virus Infection and Replication

Measles virus (MV) is an enveloped virus with fusion and replication pathways that are dependent on components of the cellular membrane. Cholesterol is a compound of particular interest because of its role in membrane microdomain formation and stability. These microdomains, also known as lipid rafts, concentrate around infectious proteins on the viral envelope and the corresponding receptor proteins on the cell membrane. Previous work has shown the inhibitory effect of methyl-b cyclodextrin (MBCD), a cholesterol-sequestering agent, upon the capability of measles virus surface glycoproteins to induce cell fusion, a cytopathic effect known as syncitia. Concentrations ranging from 2.5 and 10 mM inhibited the fusion effects of these proteins by 30% in our transient expression cell fusion reporter system. This project revolves around determining the effects cholesterol depletion has on the replication in vitro of MV. The treatment of Vero/hSLAM cells with MBCD prior to infection with MV was analyzed for the effects on viral replication 24, 48, and 72 hours post-infection. The data indicated that the pre-infection treatments had a small dose dependent reduction of active virus particle production, with the 10 mM treatment reducing the particle amount by a factor of 10 at the 48 hour post-infection time point. Next, we looked at Vero/hSLAM cells being infected with MV, followed by treatment with MBCD. This step supported the dose dependent effects on the Vero/hSLAM cells and syncytia formation. MBCD concentrations of 5 mM were able to reduce MV infectivity by 14% without a major effect on cell viability.  In sum, cholesterol content is not only important for the development of MV entry and syncitia formation, but also for virus replication.