Fig. 3. Small-molecule enhancement of miRNA and RNAi pathways by enoxacin inhibits the establishment of the ZIKV placental niche and rescues ZIKV-associated fetal growth restriction in a gnotobiotic mouse model of perinatal infection.
A, Experimental workflow: Timed mated gnotobiotic Swiss/Webster mice (n=4 dams mock+PBS vehicle control, n=5 mock+enoxacin, n=5 ZIKV+vehicle, n=6 ZIKV+enoxacin) received daily intraperitoneal injections with enoxacin (10 mg/kg) or a PBS vehicle control. Consistent with our previous gestational ZIKV exposure model, mice were inoculated with subcutaneous injections of ZIKV (strain HN16, 1×105 PFU) or mock-infected with PBS at E7.5, E8.5, and E9.5. Experiments ended on E18.5 when Cesareans were performed. B, Fetuses were immediately weighed to determine fetal growth restriction (n=56 fetuses mock+vehicle, n=30 mock+enoxacin, n=58 ZIKV+vehicle, n=43 ZIKV+enoxacin). C, RNA was extracted from placental tissue and viral loads were determined by 1-step RT-qPCR probing for the ZIKV envelope gene (ZIKV-ENV; n=6 placentae from 3 dams mock, n=6 placentae from 3 dams ZIKV+vehicle, n=12 placentae from 6 dams ZIKV+enoxacin). ZIKV was not detected in mock-infected controls or ZIKV+enoxacin placentae, but positive in 4 of 6 ZIKV+vehicle placentae (Ct-threshold <35). Significant differences were determined by two-tailed Mann-Whitney tests with significance defined as p<0.05. Error bars represent the standard error of the mean.