Alphavirus determinants of microvascular endothelial cell infection

Project Summary Alphaviruses are mosquito-transmitted human pathogens capable of explosive outbreaks and devastating disease. Alphaviruses cause a viremic infection where virus can be disseminated throughout the organism. Microvascular endothelial cells play critical roles in vascular homeostasis and protecting the vasculature from invading pathogens. How alphaviruses infect microvascular endothelial cells and how these cells respond to infection is a major knowledge gap. Filing the gap of viral and cellular determinants of endothelial cell infection would provide novel targets to block disseminated infection. In preliminary studies to understand chikungunya virus (CHIKV) infection in primary human cardiac microvascular endothelial cells (hCMECs), we found that the Indian Ocean Lineage of CHIKV (CHIKV-IOL) was completely restricted in hCMECs, while Asian lineages of CHIKV and other alphaviruses were not. When we addressed where in the viral life cycle CHIKV was restriction, we found CHIKV-IOL to be blocked at viral entry and egress, and not genome replication. These exciting preliminary data allow us to hypothesize that there are both viral and host determinants that restrict CHIKV-IOL in microvascular endothelial cells at multiple steps in the life cycle. We will test this hypothesis using primary human microvascular endothelial cells and identifying the CHIKV-specific viral factors that contribute to hCMEC infection (Aim 1) and investigating hCMEC cellular factors and pathways that restrict CHIKV-IOL (Aim 2). Understanding how pathogenic alphaviruses are restricted in primary human cells will identify viral and host pathways we can target to block virus infection, spread, and disease.