The FDA-approved drug sofosbuvir inhibits Zika virus infection

Abstract

The rapidly expanding Zika virus (ZIKV) epidemic has affected thousands of individuals with severe cases causing Guillain-Barré syndrome, congenital malformations, and microcephaly. Currently, there is no available vaccine or therapy to prevent or treat ZIKV infection. We evaluated whether sofosbuvir, an FDA-approved nucleotide polymerase inhibitor for the distantly related hepatitis C virus, could have antiviral activity against ZIKV infection. Cell culture studies established that sofosbuvir efficiently inhibits replication and infection of several ZIKV strains in multiple human tumor cell lines and isolated human fetal-derived neuronal stem cells. Moreover, oral treatment with sofosbuvir protected against ZIKV-induced death in mice. These results suggest that sofosbuvir may be a candidate for further evaluation as a therapy against ZIKV infection in humans.

Figure 1. Sofosbuvir reduces Zika virus titer in Huh-7 and Jar cells

Huh-7 and Jar cells were treated with concentrations of Sofosbuvir from 500 μM to 1 μM and concurrently infected with ZIKV PRVABC59, Dakar 41519, or Paraiba strains at a MOI of 0.1. Plates were incubated at 37°C for 72 h and viral titers at each concentration were calculated by plaque assay (A–C) and qRT-PCR (D–F). Results are the average of three independent biological replicates with standard deviation shown.

Figure 2. Sofosbuvir cytotoxicity in Huh-7 and Jar cells

Huh-7 and Jar cells were seeded in 96 well plates and allowed to attach overnight. Sofosbuvir was added from 200 μM to 0.4 μM and plates were incubated for 72 h. CellTiter-Glo reagent (Promega) was added in equal volume to media and wells were read for luminescence after 10 minutes at 37°C. Results are the average of three independent biological replicates with standard deviation shown.

Figure 3. Sofosbuvir reduces ZIKV infection in human fetal-derived neuronal stem cells

Human NSCs derived from fetal hindbrain or cerebral cortex were infected with ZIKV Paraiba at an MOI of 5 and treated with the indicated concentrations of sofosbuvir. A–B. Forty-eight hours later cells were harvested, fixed, permeabilized, stained with an anti-E protein antibody, and processed by flow cytometry. The data is pooled from three independent experiments, each performed in triplicate. The error bars indicate standard deviations. *, P < 0.05; **, P < 0.01; ****, P < 0.0001 (one-way ANOVA with multiple comparisons correction compared to 0 μM). C. Cytotoxicity analysis of sofosbuvir in human NSCs. NSCs were incubated with the indicated concentrations sofosbuvir for 48 hours, then cell viability was determined using CellTiter-Glo. The data is pooled from two independent experiments performed in duplicate. D. Flow cytometry histograms from data in panels A and B showing inhibitory effect of sofosbuvir against ZIKV infection in human NSCs. One representative experiment of three is shown.

Figure 4. Therapeutic effect of sofosbuvir in mice

Five week-old WT C57BL/6 mice were treated at day −1 with 2 mg of anti-Ifnar1 blocking mAb. On day 0, animals were inoculated via a subcutaneous route in the footpad with 10⁵ FFU of mouse-adapted ZIKV Dakar. On day 1, oral therapy was initiated with ~33 mg/kg/day sofosbuvir dissolved in Kool-Aid® or Kool-Aid® vehicle control. Survival (A) and aggregate body weights (B) were recorded. Results are pooled from two independent experiments with a total of n = 10 in each group. *, P < 0.05 (log-rank test).