Identification of small molecule inhibitors targeting the Zika virus envelope protein

The recent emergence of Zika virus, a mosquito-borne flavivirus, in the Americas has shed light on the severe neurological diseases associated with infection, notably congenital microcephaly in newborns and Guillain-Barré syndrome in adults. Despite the recent focus on Zika virus, there are currently no approved vaccines or antiviral therapies available to treat or prevent infection. In this study we established a competitive amplified luminescent proximity homogeneous assay (ALPHAscreen) to identify small molecule inhibitors targeting the envelope protein of Zika virus (Zika E). We utilized this assay to screen two libraries of nearly 27,000 compounds and identified seven novel inhibitors of Zika E. Characterization of these primary screening leads demonstrated that inhibition of Zika virus occurs at non-cytotoxic concentrations for all seven lead compounds. In addition, we found that all seven lead compounds have potent activity against the closely related dengue virus 2 but not vesicular stomatitis virus, an unrelated enveloped virus. Biochemical experiments indicate that these compounds act by preventing E-mediated membrane fusion. This work highlights a new method for the discovery and optimization of direct-acting antivirals targeting the E protein of Zika and other flaviviruses.