Fig 2: Mmp2 mRNA expression increases with age in sun-exposed human skin and correlates with AhR pathway expression.(A) MMP mRNA expression in sun-exposed human skin. (B) Mmp2 mRNA expression with increasing age in human skin. Correlations between MMP expression and (C) Ahr and (D) Kyat2 mRNA in human skin across donor demographics (OM, older males; YM, younger males; OF, older females; YF, younger females). Color represents correlation coefficients. Size represents P values. Crossed-out circles indicate nonsignificant correlations (P > 0.05). All data are log10-transformed TPM values from GTEx. n = 234 male sun-exposed samples, 467 female sun-exposed samples, 193 male sun-protected samples, and 411 female sun-protected samples. P values were calculated by Pearson’s correlation, unpaired 2-tailed Mann-Whitney test, or 1-way ANOVA; ****P < 0.0001.

Fig 3: Inhibition of AHR still restricts HSV-1 infection in STAT1−/− HFF-1 cells. α-NF- or mock-stimulated WT and STAT1−/− HFF-1 cells were infected with GFP-expressing HSV-1 for 24 h. (A) The percentages of GFP-positive cells were determined using flow cytometry. (B) The inhibition rate was determined by the percentage of GFP+ cells in the DMSO- or α-NF-treated group divided by that of the untreated group. (C) Viral titers in each group were determined by a TCID50 assay. *, P < 0.05; **, P < 0.01. Data are shown as means ± SEM.

Fig 4: SP1 binding to promoter region is required for UVB-mediated induction of Mmp2 and Mmp11.(A and B) HaCaT keratinocytes were transfected with siNC or siSP1 and irradiated with 100 mJ/cm2 UVB. Cells were lysed 24 hours later for analysis. (A) Mmp2 mRNA was measured by RT-qPCR and normalized to Hprt1 and siNC-transfected samples (n = 3). (B) Protein levels of MMP2 and β-Actin were measured by Western blot. Relative densitometry measurements are shown for MMP2. (C) HaCaT keratinocytes were transfected with indicated siRNA, irradiated with UVB, and subsequently treated with DMSO or 25 nM TCDD. Cells were lysed 24 hours later for analysis. Mmp2 mRNA was measured by RT-qPCR and normalized to Hprt1 (n = 3). (D) HaCaT cells were irradiated with UVB and lysed 24 hours later. Enrichment of AhR and SP1 at MMP promoter regions was measured by ChIP-PCR, normalizing to input samples and nonirradiated samples (n = 3). (E) HaCaT cells were cotransfected with Renilla luciferase construct and one of the following: an empty firefly luciferase construct (Emp), a firefly luciferase construct containing AhR response elements (XRE), WT MMP2 promoter (MMP2 WT), SP1 binding site mutant MMP2 promoter (MMP2 mSP1), WT MMP11 promoter (MMP11 WT), or SP1 binding site mutant MMP11 promoter (MMP11 mSP1). Cells were irradiated with UVB and lysed 24 hours later. Fold induction of relative luciferase units (RLU) was calculated by normalizing firefly luciferase activity to Renilla luciferase activity and nonirradiated samples (n = 3). Data are means ± SEM. P values were calculated by 1-way ANOVA or 2-way ANOVA. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.

Fig 5: AHR−/− THP-1 cells are resistant to HSV-1 infection. WT and AHR−/− THP-1 cells were infected with GFP-expressing HSV-1. (A to C) GFP expression at 24 h was determined using flow cytometry (A), and the percentage of GFP-positive cells and mean fluorescence intensity are shown in histograms (B) and confocal microscopy images (C). (D) WT or AHR−/− THP-1 cells were infected with HSV-1 for 1, 6, 24, and 48 h. Viral titers were determined by a TCID50 assay. (E and F) AHR−/− cells were pretreated with DMSO or α-NF and infected with GFP-expressing HSV-1, GFP expression was determined by flow cytometry (E), and the percentage of GFP+ cells and the mean fluorescence intensity are shown in histograms (F). *, P < 0.05; **, P < 0.01. Data are shown as means ± SEM.