High expression of IDO1 and TGF-β1 during recurrence and post infection clearance with Chlamydia trachomatis, are independent of host IFN-γ response

Abstract

Background Chlamydia trachomatis infections in women continue to be a major public health concern due to their high prevalence and consequent reproductive morbidities. While antibiotics are usually efficient to clear the Chlamydia , repeat infections are common and may contribute to pathological outcomes. Interferon-gamma (IFN-γ)-mediated immunity has been suggested to be protective against reinfection, and represent an important anti-chlamydial agent, primarily via the induction of indoleamine-2,3 dioxygenase 1 (IDO1) enzyme. IDO1 catalyzes the degradation of tryptophan, which can eliminate C. trachomatis infection in vitro. Here, we sought to measure IDO1 expression levels and related immune markers during different C. trachomatis infection statuses (repeated vs single infection vs post antibiotic treatment), in vitro and in vivo. Methods In this study, we measured the expression levels of IDO1 and immune regulatory markers, transforming growth factor β1 (TGF-β1) and forkhead box P3 (FoxP3), in vaginal swab samples of C. trachomatis -infected women, with either single or repeated infection. In addition, we used an in vitro co-culture model of endometrial carcinoma cell-line and peripheral blood mononuclear cells (PBMCs) to measure the same immune markers. Results We found that in women with repeated C. trachomatis infections vaginal IDO1 and TGF-β1 expression levels were significantly increased. Whereas, women who cleared their infection post antibiotic treatment, had increased levels of IDO1 and TGF-β1, as well as FoxP3. Similarly, using the in vitro model, we found significant upregulation of IDO1 and TGF-β1 levels in the co-culture infected with C. trachomatis . Furthermore, we found that in PBMCs infected with C. trachomatis there was a significant upregulation in IDO1 levels, which was independent of IFN-γ. In fact, C. trachomatis infection in PBMCs failed to induce IFN-γ levels in comparison to the uninfected culture. Conclusions Our data provide evidence for a regulatory immune response comprised of IDO1, TGF-β1 and FoxP3 in women post antibiotic treatment. In this study, we demonstrated a significant increase in IDO1 expression levels in response to C. trachomatis infection, both in vivo and in vitro, without elevated IFN-γ levels. This study implicates IDO1 and TGF-β1 as part of the immune response to repeated C. trachomatis infections, independently of IFN-γ. Electronic supplementary material The online version of this article (10.1186/s12879-019-3843-4) contains supplementary material, which is available to authorized users.

Epidermal Growth Factor Receptor and Transforming Growth Factor β Signaling Pathways Cooperate To MediateChlamydiaPathogenesis

“…We investigated the hypothesis that TGF-␤ signaling cooperates with the EGFR signaling pathway for the cytoskeletal reorganization that supports optimal chlamydial inclusion development and for stable EMT induction. Figure 1a confirms previous reports (40,41) that upregulated TGF-␤ expression is induced during chlamydial infection (P Ͼ 0.0001). The induction occurred within 6 h of infection of epithelial cells.…”

“…It has been established that Chlamydia binds EGFR and activates the EGFR signaling pathway, which plays a crucial role in host cell invasion and cytoskeletal reorganization for a productive infection with optimal inclusion development (8,9,(32)(33)(34)(35)(36)42). The EGFR and TGF-␤ signaling pathways also often synergize to mediate cytoskeletal reorganization, leading to stable EMT induction (20,43), and Chlamydia induces EMT (6) as well as upregulates TGF-␤ expression in humans and animals (40,41). However, the involvement of TGF-␤ in chlamydial inclusion development and chlamydia-induced EMT is unknown.…”

“…Like the EGF/EGFR system, the serine/threonine kinase TGF-␤/TGF-␤R signaling cascade induces cytoskeletal remodeling and cellular functions, and it synergizes with the EGFR pathway in cellular regulation, which leads to stable EMT and other pathological consequences, such as fibrosis and tumor progression and invasiveness (37)(38)(39). Although Chlamydia also upregulates TGF-␤ expression in both animals and humans, it is thought to play an immunoregulation function predominantly (40,41), so its role in infectivity or inclusion development and Chlamydia-induced EMT is unknown. In this study, we extended our previous observation relating to Chlamydia-induced EMT (6) by testing the hypothesis that the TGF-␤R and EGFR signaling pathways cooperate to ensure a productive Chlamydia infection, leading to EMT induction and development of complications.…”

Differences in the Genital Microbiota in Women Who Naturally Clear Chlamydia trachomatis Infection Compared to Women Who Do Not Clear; A Pilot Study

“…In our cohort, the levels of IFNg measured were significantly below those needed to clear Ct infections in in vitro models (Shemer and Sarov, 1985;Arno et al, 1990), suggesting additional factors may be at work in vivo in women. In vitro studies by Ziklo et al have shown that Ct can induce IDO1 expression in the absence of IFNg, further suggesting alternative regulatory pathways for IDO-1-induced tryptophan degradation (Ziklo et al, 2019). Additionally, Jordan et al found decreased IFNg concentrations in those that cleared Ct compared to those with a persistent infection, which could reflect the decreased production of IFNg once Ct is cleared (Jordan et al, 2017).…”

Interferon gamma, TGF-β1 and RANTES expression in upper airway samples from SARS-CoV-2 infected patients

“…Glyceraldehyde 3-phosphate dehydrogenase gene (GAPDH) was used as housekeeping gene. RANTES and TGF-β1 expression were measuring according to Ziklo et al protocols [ 13 ]; first mRNA was reverse-transcribed using radom primers and SuperScript® Reverse Transcriptase Kit (Invitrogen, Life Technologies). cDNA synthesized was use as template in PCR reaction using QuantiFastTMSYBR® Green PCR Kit (QIAGEN, Germany).…”