Human Cytomegalovirus Use and Manipulation of Host Phospholipids

Abstract

Human cytomegalovirus (HCMV) is a widely-spread β-herpesvirus that causes a congenital infection that results in devastating disabilities in newborns. Infection also causes life-threatening disease in people with compromised immune systems. HCMV requires viral remodeling of host cell metabolism to obtain metabolites and lipids to support replication and contains an envelope made of lipids ‘stolen’ from the host. Envelopment is a crucial step in the HCMV life cycle and requires numerous host cell lipids, most prominently phospholipids. I hypothesized that HCMV upregulates the production of cellular phospholipids and uses host cell lipid transport proteins to transport those phospholipids to the viral envelope. I used tandem LC-MS/MS to quantitatively determine HCMV manipulation of the abundance of phospholipids. I found that HCMV significantly upregulates phosphatidylcholine (PC) lipids and identified a required viral protein: pUL37x1. PC lipids are transferred between membranes by phosphatidylcholine transfer protein (PC-TP). I found that HCMV upregulates PC-TP expression during infection, suggesting that it is important to infection. To determine the role of PC-TP in virus replication, I used a small molecule inhibitor and a CRISPR/Cas9 knockout of PC-TP. My preliminary data indicates that the loss of PC-TP activity reduces HCMV infection late in the viral replication cycle, consistent with my hypothesis. Additionally, I analyzed how the loss of PC-TP affects HCMV remodeling of host lipid metabolism. Overall, my findings demonstrate that HCMV upregulates cellular phospholipids and that PC-TP may play a role in transporting those lipids in viral replication