Project Two: Small Molecule Inhibitors of Ebola Virus Infection
Ebola virus (EboV) is a highly pathogenic enveloped virus that causes outbreaks of zoonotic infection in Africa. The unpredictable onset, ease of transmission, rapid progression of disease, high mortality, and lack of effective vaccine or anti-viral therapy have created a high level of public concern about EboV.
EboV are enveloped viruses that enter cells by attachment of the envelope glycoprotein GP to cell surface lectins and uptake into cytoplasmic vesicles by macropinocytosis16,17. Virus-containing vesicles fuse with endosomes, and virus particles are transported to lysosomes containing host factors that activate the intrinsic membrane fusion activity of the EboV glycoprotein GP. The goal of this proposal is to identify small molecules that inhibit infection mediated by EboV GP and use these inhibitors as tools to investigate the virus entry pathway. Previously, we screened a small molecule library using a cell-based assay for infection mediated by the EboV glycoprotein GP. Three compounds, 3.0, 5.0 and 6.0, have been identified that selectively inhibit EboV infection, exhibit dynamic SAR, demonstrate an absence of cytotoxicity, and have evidence of unique targets in cells. Completed studies identified the target of the inhibitor 3.0 as the lysosome membrane protein Niemann-Pick C1 (NPC1) and demonstrated that 3.0 and its analogs interfere with the function of NPC1 as an EboV GP receptor11,13. These findings validate the use of a chemical biology approach for analysis of the EboV entry pathway. Going forward, we will determine the molecular basis for 3.0 inhibition of NPC1 (Specific Aim 3), identify the targets for EboV inhibition by 5.0 and 6.0 (Specific Aim 2), and apply this information to improve inhibitor potency and to carry out a test of anti-viral activity in mice (Specific Aim 4). To perform these studies, we will be assisted by a team of investigators with expertise in medicinal chemistry, identification of small molecule targets (SILAC), genetic screening for virus host factors, live cell imaging, and mouse models of EboV infection.