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. 2023 Aug 3;14:4668. doi: 10.1038/s41467-023-40047-w

Fig. 3. Local IFN-I response in cardiac tissue control CHIKV infection and prevent tissue damage.

Fig. 3

a Heat map showing the differentially expressed genes (FDR < 0.15) from the Hallmark IFNα response pathway for CHIKV-infected and HI-control hearts. b Top panel: representative fluorescence microscopy images from two independent repetitions showing ventricular sections of CHIKV-infected hearts and PBS control stained with anti-ISG15 and anti-vimentin antibodies. Scale= 10 μm. Bottom panel: Quantification of ISG15+ signal/field. Analysis was done on two independent fields for PBS control (n = 2), and CHIKV-infected (n = 6). c Dependence on IFN-I signaling in human primary cardiac fibroblasts during CHIKV infection. Cells were pretreated as indicated in the figure and infected with CHIKV-ZsGreen at an MOI of 0.25. Data represent three independent repetitions in technical duplicates. d IFN-I pretreatment experiments in human primary cardiac cell types. Cells were pretreated with different concentrations of recombinant IFN-α (right panel) and IFN-β (left panel) for 24 h and then infected with CHIKV-ZsGreen at an MOI of 0.25 for 24 h. For IFN-α: three independent repetitions in technical duplicates. For IFN-β: four independent repetitions in technical duplicates. e Representative fluorescence microscopy images from three independent repetitions showing CHIKV-ZsGreen WT or Ifnar1−/− infected hearts at 1 dpi. Scale= 30 μm. f Percentage of the total of infected cells (green signal) overlapping with the indicated makers (See Supplementary Fig. 1d, e). Colocalization analysis was done in three to five independent sections for n = 2 mice. g Left panel: Apoptosis staining was measured by IHC against cleaved CASP3. Scale= 50 μm. Arrows highlight apoptotic foci. Right panel: Quantifications of cleaved CASP3 nuclei versus total nuclei were performed in whole ventricular sections (LV, RV, and septum) using VisiopharmR. Each dot represents one individual mouse. PBS control (n = 5), CHIKV-infected WT (n = 5), and CHIKV-infected Ifnar1−/− mice (n = 6). Data are represented as mean ± SEM (b–d, f, g). P values were calculated using two-tailed Mann–Whitney (b), or one-way ANOVA with Dunnett’s multiple comparison test (c, d, g), or Kruskal–Wallis with Dunn’s multiple comparison test (f). Created with BioRender.com. Source data are provided as a source data file.