Figure 4
Extracellular cGAMP exaggerates the IFN-I, but not the IL-6 or TNF, response to UVB light. (A) B6 mice were shaved and injected intradermally with 100 µM ENPP1 inhibitor (STF-1084) or Vehicle (PBS), 30 min prior to the exposure to UVB light as above. Skin was biopsied 16 hr after UV exposure. (B) Fold-change in ISG expression was determined relative to vehicle-treated non-UVB exposed skin in three treatment groups: STF1084 without UVB, vehicle with UVB, and STF-1084 with UVB. (C) Skin IFN scores in vehicle and STF-1084-treated UV exposed and non-exposed (NUV) skin were calculated as sum of normalized expression levels of the same 7 ISG as in Fig. 1. (D) Fold-induction in the expression of inflammatory cytokines Tnfa, Il-6, and Il1-β were determined relative to baseline, i.e. non-irradiated vehicle-treated skin (no UV). Statistical significance was determined by Student’s t-test (n = 5, 2 independent experiments; *p < 0.05, **p < 0.01, ns = not significant).
