Identification of small molecule inhibitors targeting the Zika virus envelope protein

Abstract

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.

Identification of anti-flaviviral drugs with mosquitocidal and anti-Zika virus activity in Aedes aegypti

“…For example, serum concentration of imatinib mesylate ranges between 0.138 mg/ml and 2.816 mg/ml (median = 1.344 mg/ml) [50], which is higher than what we used for mosquito feeding (58.97 μg/ml); the patient serum level of MPA ranges from 0.45 to 6.5 mg/l (median = 2.1 mg/l) [51, 52], which is lower than that we fed mosquitoes on (32.04 μg/ml); the level of CsA in patient blood ranges from 212 to 1358 ng/ml [53], which is higher than that in blood meal can kill mosquitoes (120.26 ng/ml); the median concentration of Actinomycin D in patient plasma ranges from 24.4 to 128 μg/l between 5 and 15 min post administration [54], which is similar to that in blood meal can kill mosquitoes (125.5 ng/l). It is standard practice to use uniform concentrations when screening multiple compounds for bioactivity such as anti-viral action [17, 55]. Since we did not observe complete virus-blocking (infection intensity of zero) for any of the drugs, even at concentrations higher than patient serum levels, we did not pursue testing of lower concentrations.…”

A quantitative luciferase-based cell–cell fusion assay to measure four-serotype dengue virus E protein-triggered membrane fusion

“…3,6 Several small-molecule inhibitors screened from chemical libraries have been reported to prevent the membrane fusion required for DENV, ZIKV, or other flavivirus infections. [7][8][9][10][11][12][13][14][15][16] Since the membrane fusion is required for DENV infection, several anti-fusion human monoclonal antibodies (mAbs) derived from patients with secondary infections but not primary infections were reported to present high-avidity and potent neutralization. 17,18 These high-avidity and potent neutralizing anti-fusion mAbs would be expected to be protective in vivo.…”

Broad‐Spectrum Flavivirus Inhibitors: a Medicinal Chemistry Point of View

“…Thanks to similar lines of efforts, an AlphaScreen HTS based on the ZIKV E protein was carried on two commercially available libraries for a total of 26,954 compounds. [129] All compounds exhibiting promising IC 90 values ranging from 5.2 to 20.3 μM in the AlphaScreen were next evaluated for their antiviral activity (PRA on Vero cells). Among the most promising seven compounds, derivative 34 (Figure 9) exhibited the most potent anti-ZIKV activity (EC 90 = 5.1 μM) coupled with low toxicity (CC 50 = 98 μM).…”