Fig. 4: Sphingosine inhibits ZIKV infection in mosquitoes and cells.

a The effect of 24 common metabolites on ZIKV infection in C6/36 cells at 48 h (n = 3 biologically independent cell samples; one-way ANOVA test followed by Dunnett’s post hoc tests). Con.: ethanol or DMSO. Full metabolite names are listed in the cells, viruses, antibodies, and reagents subsection of the methods section. b The effect of mox, sph and psph common metabolites on ZIKV infection in Vero cells at 48 h (n = 3 biologically independent cell samples; one-way ANOVA test followed by Dunnett’s post hoc tests). Con.: DMSO. c The levels of sph and psph secreted by Eh_B17, Es_B36, and Eh_B56 using HPLC-Q-TOF (n = 3 biologically independent bacterial samples; one-way ANOVA test followed by Tukey’s post hoc tests). d Identifying the role of Eh_B17 and Eh_B17-mutant in lab-adapted Ae. aegypti (UGAL/Rockefeller strain) infected with ZIKV (1.0 × 10⁶ FFU/mL) for 7 d (n = 24 for both Con. and Eh_B17-mutant; n = 22 for Eh_B17; Kruskal–Wallis test followed by Dunn’s post hoc tests). Each dot represents one mosquito. Con.: LB treatment. Percentages represent the rate of mosquito infection. e Identifying the role of sph in Ae. aegypti infected with ZIKV for 7 d (n = 22 for Con., 5, 20, and 40 µM; n = 21 for 10 µM; Kruskal–Wallis test followed by Dunn’s post-hoc tests). Each dot represents one mosquito. Con.: antibiotic-treated mosquitoes infected with ZIKV and DMSO. Percentages represent the rate of mosquito infection. The two-sided Fisher’s exact test was used to compare differences in the infection rates. f Virus titers in saliva were measured using focus-forming assay at 10 d post infection (n = 15 for Con.; n = 16 for 40 µM; two-sided Mann-Whitney test). Each dot represents one saliva sample. Con.: LB treatment. g Effect of different concentrations of sph on ZIKV-infected C6/36 cells at 48 h (n = 3 biologically independent cell samples). The top of each column shows the number of infected mosquitoes relative to the total number of mosquitoes in d–f. Data are shown as mean ± SEM. The experiment was repeated twice with similar results. *P < 0.05, **P < 0.01, ***P < 0.001. ns: not significant. Source data are provided as a Source Data file.