title: Analyses of the pathways involved in early- and late-phase induction of IFN-beta during C. muridarum infection of oviduct epithelial cells.
abstract: We previously reported that the IFN-β secreted by Chlamydia muridarum-infected murine oviduct epithelial cells (OE cells) was mostly dependent on the TLR3 signaling pathway. To further characterize the mechanisms of IFN-β synthesis during Chlamydia infection of OE cells in vitro, we utilized specific inhibitory drugs to clarify the roles of IRF3 and NF-κB on both early- and late-phase C. muridarum infections. Our results showed that the pathways involved in the early-phase of IFN-β production were distinct from that in the late-phase of IFN-β production. Disruption of IRF3 activation using an inhibitor of TBK-1 at early-phase Chlamydia infection had a significant impact on the overall synthesis of IFN-β; however, disruption of IRF3 activation at late times during infection had no effect. Interestingly, inhibition of NF-κB early during Chlamydia infection also had a negative effect on IFN-β production; however, its impact was not significant. Our data show that the transcription factor IRF7 was induced late during Chlamydia infection, which is indicative of a positive feedback mechanism of IFN-β synthesis late during infection. In contrast, IRF7 appears to play little or no role in the early synthesis of IFN-β during Chlamydia infection. Finally, we demonstrate that antibiotics that target chlamydial DNA replication are much more effective at reducing IFN-β synthesis during infection versus antibiotics that target chlamydial transcription. These results provide evidence that early- and late-phase IFN-β production have distinct signaling pathways in Chlamydia-infected OE cells, and suggest that Chlamydia DNA replication might provide a link to the currently unknown chlamydial PAMP for TLR3.
authors: Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, People's Republic of China.
authors: Sishun
authors: S
authors: Hu
authors: Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.
authors: Kristen L
authors: KL
authors: Hosey
authors: Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.
authors: Wilbert A
authors: WA
authors: Derbigny
mesh_terms: D000818:Animals; D002460:Cell Line; D023502:Chlamydia muridarum / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D004261:DNA Replication / Q000187:drug effects; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology*; D005260:Female; D006801:Humans; D050838:Interferon Regulatory Factor-3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D050839:Interferon Regulatory Factor-7 / Q000378:metabolism; D016899:Interferon-beta / Q000096:biosynthesis* / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010057:Oviducts / Q000166:cytology*; D011743:Pyrimidines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013876:Thiophenes / Q000494:pharmacology; D013997:Time Factors; D051196:Toll-Like Receptor 3 / Q000378:metabolism
chemical_list: C579675:BX795; C494232:IRF3 protein, human; C494234:IRF7 protein, human; D050838:Interferon Regulatory Factor-3; D050839:Interferon Regulatory Factor-7; D016328:NF-kappa B; D011743:Pyrimidines; C495344:TLR3 protein, human; D013876:Thiophenes; D051196:Toll-Like Receptor 3; D016899:Interferon-beta