(A and B) Bmal1–luciferase reporter assay. Human NTERT keratinocytes were transduced with Bmal1–luciferase reporter construct and starved of growth supplement overnight before treatment with vehicle or 10 μM SR8278. Cells were harvested (A) every 6 hours and (B) at 24 hours for RLU measurements (n = 4 samples). (C) Immunostaining for HSV-1 antigen in human epidermal explants infected with HSV-1 and treated with vehicle or 10 μM SR8278. Scale bar: 500 μm. (D) ImageJ (Fiji) quantification of viral immunofluorescence normalized to nuclear staining (n > 5,000 cells quantified per condition). (E) qPCR of HSV-1 viral gene UL29 relative to human KRT14 in epidermal skin infection (n = 4 skin explants). (F) Immunostaining for HSV-1 antigen in human NTERT keratinocytes (MOI, 0.01) transfected with siCtrl or siBMAL1 and supplemented with vehicle or 10 μM SR8278. Scale bar: 160 μm. (A–F) P values were obtained via 2-tailed Student’s t test. (G) ImageJ (Fiji) quantification of relative viral immunofluorescence normalized to nuclear staining. Data for quantification of siCtrl (vehicle) are the same as used in Figure 4E (n > 400 cells/condition quantified). (G–H) P values were obtained using 1-way ANOVA with multiple comparisons. (H) qPCR of HSV-1 viral gene UL29 in cell culture–conditioned medium of primary keratinocytes (MOI, 0.01) transfected with siBMAL1 or siCLOCK and infected with HSV-1 (n = 3). Graphs represent averages of relative viral DNA or viral protein immunofluorescence normalized to human KRT14 or nuclear staining ± SEM. P values were obtained using 1-way ANOVA with multiple comparisons. *P ≤ 0.05, **P ≤ 0.01, ****P ≤ 0.0001. ZT, Zeitgeber time.