Indiana University-Purdue University Indianapolis (IUPUI) / Progression of Chlamydia into upper reproductive tract epithelium and the induction of subsequent immune responses to infection are major contributors to Chlamydia-induced pathogenesis of the genital tract. We reported that C. muridarum infection of the oviduct epithelial cells (OEs) secrete IFN-β in a TLR3 dependent manner. However, we showed that the C. muridarum infected TLR3-deficient OEs were still able to secrete minimal amounts of IFN-β into the supernatants, which is suggestive that there are other signaling pathways that contribute to Chlamydia-induced IFN-β synthesis in these cells. Previous studies describing the activation of the JAK/STAT signaling pathway during Chlamydia infection of cervical epithelial cells proposes a putative role for STAT1 in the synthesis of type I IFNs during Chlamydia infection. The present study investigated the role of STAT1 in Chlamydia-induced IFN-β production in OEs. OEs were infected with Chlamydia muridarum and analyzed at 24 hours by RT-PCR and western blot to determine STAT1 expression. STAT (-/-) OEs were infected and IFN-β production measured by ELISA. Quantitative real-time PCR analyses were performed at 6 and 16 hour post-infection to elucidate the mechanisms involved in IFN-β production during infection. Fluorescent microscopy was used to observe changes in Chlamydia replication. STAT1 activation and expression were significantly increased in wild-type (WT) OEs upon infection. TLR3 (-/-) OEs showed diminished STAT1 protein activation and expression. Augmented STAT1 protein expression corresponded to STAT1 mRNA levels. ELISA analyses revealed significantly less IFN-β production in infected STAT1 (-/-) OEs compared to WT OEs. Quantitative real-time PCR data showed that gene expression of IFN-β and of type I IFN signaling components were significantly increased during late stage Chlamydia infection, dependent on STAT1. Temporal regulation and increases in expression of IFN-α subtypes during infection were STAT1-dependent. Our results implicate STAT1-mediated signaling as a contributor to the C. muridarum-induced synthesis of IFN-β and other type I IFNs in OEs. We previously described a major role for TLR3 in the early-stage Chlamydia-induced synthesis of IFN-β in OEs; the results from this study suggest a role for STAT1 in the synthesis of type I IFNs that occurs during early and late stages of infection.
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/3742 |
| Date | 10 December 2013 |
| Creators | Hosey, Kristen L. |
| Contributors | Derbigny, Wilbert A, Blum, Janice Sherry, 1957-, Goebl, Mark, 1958-, Johnson, Raymond M., Kaplan, Mark H. |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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