Host Regulation of Ebola Virus Egress and Spread: Role of Cytoskeletal Filamin Proteins

Abstract

Ebola virus (EBOV) causes severe hemorrhagic fever associated with high mortality rates in humans. EBOV and other filoviruses are emerging BSL‐4 pathogens for which the development of novel and effective therapeutics is urgently needed. Egress and spread of EBOV is mediated by the VP40 matrix protein (eVP40), whereby expression of eVP40 alone directs the production and egress of virus‐like particles (VLPs) that accurately mimics the budding process of live infectious virus. We have shown that eVP40 hijacks or recruits select host proteins to facilitate the budding process. On the other hand, we have also identified several host proteins that interact with eVP40 to negatively regulated eVP40‐mediated budding. Thus, a better understanding of the eVP40‐host interactome will provide important insights into the mechanisms of virus egress and spread, as well as inform about potential targets for the development of novel antiviral therapeutics. Here, we investigated the possible role for host filamin A and B proteins (actin crosslinking proteins that function in cell morphology and migration at the plasma membrane) in regulating both entry and egress of EBOV. Toward this end, we employed filamin A (FLNaKD) and filamin B knockdown cells (FLNbKD) to assess EBOV entry by using live EBOV, as well as recombinant viruses and/or pseudotypes expressing the EBOV surface glycoprotein (GP). We also used the KD cells to assess virus egress by using our well‐established eVP40 VLP budding assay. In sum, our results indicate that expression of host filamin proteins appears to be important for EBOV to efficiently complete different stages of its lifecycle.