STING promotes the growth of tumors characterized by low antigenicity via IDO activation

STING promotes the growth of tumors characterized by low antigenicity via IDO activation. resistance but not susceptibility to Naxagolide HBV. High\level expression of STING was implicated in HBV\brought on induction of type III IFN and a pro\inflammatory cytokine, IL\6. In contrast, RNAi\mediated knockdown of Naxagolide STING inhibited type III IFN induction and restored the levels of HBV total transcript in an HBV\infected cell clone exhibiting resistance to HBV. These results Naxagolide suggest that STING regulates susceptibility to HBV by its expression levels. STING may thus be a novel target for anti\HBV strategies. test. mRNA induction after HBV contamination Rabbit Polyclonal to KCNK1 between NKNT\3/NTCP #28.3.8 and #28.3.25.13 cells (Figure ?(Figure3D).3D). At 5 or 9?days after HBV contamination, mRNA was strongly induced in NKNT\3/NTCP #28.3.25.13 cells, but not in #28.3.8 cells (Figure ?(Figure3D).3D). These results suggest that HBV contamination induces the innate immune response in cell clone exhibiting resistance but not susceptibility to HBV. We next examined whether type I and/or type III IFN was required for mRNA induction after HBV contamination in NKNT\3/NTCP #28.3.25.13 cells. Interestingly, at 9?days after HBV contamination, and (type III IFN) mRNA, but not (type I IFN) mRNA, were induced in NKNT\3/NTCP #28.3.25.13 cells (Figure ?(Physique3E,F).3E,F). In addition, mRNA (Physique ?(Physique3G),3G), ISG15 (Physique ?(Physique3H),3H), and ISG56 (Physique ?(Physique3H)3H) were induced at 9?days after HBV contamination, but not mock or ultraviolet\inactivated HBV (UV\HBV) contamination, in NKNT\3/NTCP #28.3.25.13 cells. Consistent with these results, HBV Naxagolide induced and mRNA, in HBV\replicating HepG2.2.15 cGAS/STING cells stably expressing both exogenous cGAS and STING10 (Determine ?(Figure3I).3I). In addition, the induction levels of and mRNA in HepG2.2.15 cGAS/STING cells were higher than those in HepG2.2.15 cGAS GSAA/STING cells stably expressing both exogenous cGAS GSAA (the inactive mutant of cGAS) and STING.10 These results suggest that HBV induces type III IFN through the cGAS/STING signaling pathway in NKNT\3/NTCP #28.3.25.13 cells, but not in #28.3.8 cells. These results also suggest that the expression levels of cGAS/STING signaling pathway\associated host factor(s) are different between NKNT\3/NTCP #28.3.8 cells and #28.3.25.13 cells. Open in a separate window Physique 3 HBV induced type III IFN in NKNT\3/NTCP #28.3.25.13 cells exhibiting resistance to HBV. A, Outline of cell cloning by the limited dilution method. NKNT\3/NTCP #28.3.25.13 and #28.3.30.20.3 cells were selected by their distinct serial limited dilution, respectively. Blue arrows with dashed lines show the selection of Naxagolide a cell clone exhibiting resistance to HBV. B, Quantitative RT\PCR analysis of the amounts of HBV total transcript in HBV\infected NKNT\3/NTCP #28.3.8, #28.3.25.13, or #28.3.30.20.3 cells. *mRNA in HBV\infected NKNT\3/NTCP #28.3.8 or #28.3.25.13 cells. Cells were infected with HBV at 103 or 104 HBV genome equivalents per cell, respectively. Each mRNA level was calculated relative to the level in mock\infected NKNT\3/NTCP #28.3.25.13 cells, which was set at 1. *and mRNA in HBV\infected NKNT\3/NTCP #28.3.8 or #28.3.25.13 cells. Cells were infected with HBV at 103 or 104 HBV genome equivalents per cell, respectively. Each mRNA level was calculated as described in Physique ?Figure3D.3D. ND: not detected. NS: not significant, *mRNA in HBV\infected NKNT\3/NTCP #28.3.8 or #28.3.25.13 cells. Cells were infected with HBV at 103 or 104 HBV genome equivalents per cell, respectively. Each mRNA level was calculated as described in Physique ?Figure3D.3D. NS; not significant versus mock\infected NKNT\3/NTCP #28.3.25.13 cells. G, (left panel) Quantitative RT\PCR analysis of the amounts of HBV total transcript in mock\, HBV\, or UV\HBV\infected NKNT\3/NTCP #28.3.25.13 cells. (right panels) Quantitative RT\PCR analysis of mRNA in mock\, HBV\, or UV\HBV\infected NKNT\3/NTCP #28.3.25.13 cells. Each mRNA level was calculated as described in Physique ?Figure3D.3D. **mRNA in HepG2.2.15 cGAS/STING cells. Each mRNA level was calculated relative to the level in HepG2.2.15 Cont cells, which was set at 1. *and mRNA induction in NKNT\3/NTCP #28.3.25.13 cells was several times higher than that in NKNT\3/NTCP #28.3.8 cells (Figure ?(Figure4A).4A). We next tried to identify the host factor(s) responsible for the higher responsiveness to p\dGdC in NKNT\3/NTCP #28.3.25.13 cells. Among cGAS/STING signaling pathway\associated host factor(s), we found that mRNA (Physique ?(Figure4B)4B) and STING protein (Figure ?(Physique4C)4C) were highly.