Project description:Genital C. trachomatis (CT) infection may cause pelvic inflammatory disease (PID) that can lead to tubal factor infertility (TFI). Understanding the pathogenesis of chlamydial complications including the pathophysiological processes within the female host genital tract is of immense importance in preventing adverse pathology. In this study, we tested the hypothesis that the miRNA profile of a acute primary chlamydial infection characterized by temporary inflammation versus the profile associated with chronic genital chlamydial infections that might precipitate PID or TFI will be different. Thus, we analyzed and compared the differentially expressed miRNAs that regulate CT pathogenesis after a single genital infection and those involved in the development of PID and TFI after repeat infections. Mice (Mus musculus) were infected with Chlamydia muridarum once or twice with a month interval between infections, and then sacrificed and genital tract tissues were collected at 1, 2, 4, and 8 weeks after infection. miRNAs were differentially expressed in both first infection and the re-infection; however, the miRNA expression profile was different for both groups. Pathway analysis showed that, amongst other functions, the differentially regulated miRNA might be regulating several pathways involved in cellular and tissue development, disease conditions and toxicity. Grant number: 1SC2HD086066-03 Funding source: Eunice Kennedy Shriver National Institute of Child Health & Human Development Title: Discovering Novel Biomarkers Predictive of Tubal Infertility Caused by Chlamydia. Principal investigator: Yusuf Omosun Date: 05/01/2015-04/30/2019
Project description:Comparison of two Chlamydia-specific CD4 T cells that are dependent on iNOS to terminate Chlamydia replication in epithelial cells to two Chlamydia-specific CD4 T cells that are iNOS-independent: Chlamydia trachomatis urogenital serovars replicate predominately in epithelial cells lining the reproductive tract. This tissue tropism poses a unique challenge for the host immune system and vaccine development. Studies utilizing the Chlamydia muridarum mouse model have shown that CD4 T cells are critical and sufficient to clear primary genital tract infections. In vitro studies have shown that CD4 T cells terminate the infection in epithelial cells by up regulating epithelial iNOS transcription and nitric oxide production via IFN-gamma and T cell-epithelial cell interactions mediated by LFA-1-ICAM-1. This mechanism however is not critical as iNOS-deficient mice clear infections normally, and IFN-gamma deficient mice clear 99.9% of the infection with near normal kinetics. We recently showed that a subset of Chlamydia-specific CD4 T cell clones were able to terminate replication in epithelial cells using a mechanism that was independent of iNOS and IFN-gamma. That mechanism did not require physical lysis of infected cells, but instead required T cell degranulation. In this study we advanced that work using gene expression microarrays to compare CD4 T cell clones that are able to terminate epithelial replication via an iNOS-independent mechanism to iNOS-dependent CD4 T cell clones. Micro array experiments showed that Plac8 was differentially expressed by the T cell clones having the iNOS-independent mechanism. Plac8-deficient mice had significantly delayed clearance of C. muridarum genital tract infections, and that the large majority of Plac8-deficient mice treated with the iNOS-inhibitor N-monomethyl-L-arginine (MLA) were unable to resolve a C. muridarum genital tract infection over 8 weeks. These results demonstrate that there are two independent and redundant T cell mechanisms for clearing C. muridarum genital tract infections; one mechanism dependent on iNOS, the other mechanism dependent on Plac8. While T cells subsets have been defined by cytokine profiles, there are important subdivisions by effector functions, in this case CD4Plac8. Gene expression study using 4 experimental groups with 4 replicates each.
Project description:Genital infection by Chlamydia trachomatis is the most common bacterial sexually transmitted disease worldwide, posing a significant threat to reproductive health. Its ability to persist silently in the host often delays treatment, leading to chronic inflammation and complications such as pelvic inflammatory disease, ectopic pregnancy, and infertility in females. Despite progress in understanding C. trachomatis pathogenesis, studies in primary cells remain limited. This study explored the interaction between C. trachomatis and primary human endocervical cells, revealing extensive host transcriptional changes, including strong inflammatory responses (IFN-α, IFN-γ, TNF-α), suppression of E2F targets, DNA repair, G2M checkpoint, and oxidative phosphorylation, indicating mitochondrial dysfunction. Downregulation of electron transport chain genes and phenotypic analysis showed selective TCA cycle impairments in succinate and citrate utilization. Further research is needed to uncover the mechanisms behind C. trachomatis-mitochondria interactions.
Project description:Comparison of two Chlamydia-specific CD4 T cells that are dependent on iNOS to terminate Chlamydia replication in epithelial cells to two Chlamydia-specific CD4 T cells that are iNOS-independent: Chlamydia trachomatis urogenital serovars replicate predominately in epithelial cells lining the reproductive tract. This tissue tropism poses a unique challenge for the host immune system and vaccine development. Studies utilizing the Chlamydia muridarum mouse model have shown that CD4 T cells are critical and sufficient to clear primary genital tract infections. In vitro studies have shown that CD4 T cells terminate the infection in epithelial cells by up regulating epithelial iNOS transcription and nitric oxide production via IFN-gamma and T cell-epithelial cell interactions mediated by LFA-1-ICAM-1. This mechanism however is not critical as iNOS-deficient mice clear infections normally, and IFN-gamma deficient mice clear 99.9% of the infection with near normal kinetics. We recently showed that a subset of Chlamydia-specific CD4 T cell clones were able to terminate replication in epithelial cells using a mechanism that was independent of iNOS and IFN-gamma. That mechanism did not require physical lysis of infected cells, but instead required T cell degranulation. In this study we advanced that work using gene expression microarrays to compare CD4 T cell clones that are able to terminate epithelial replication via an iNOS-independent mechanism to iNOS-dependent CD4 T cell clones. Micro array experiments showed that Plac8 was differentially expressed by the T cell clones having the iNOS-independent mechanism. Plac8-deficient mice had significantly delayed clearance of C. muridarum genital tract infections, and that the large majority of Plac8-deficient mice treated with the iNOS-inhibitor N-monomethyl-L-arginine (MLA) were unable to resolve a C. muridarum genital tract infection over 8 weeks. These results demonstrate that there are two independent and redundant T cell mechanisms for clearing C. muridarum genital tract infections; one mechanism dependent on iNOS, the other mechanism dependent on Plac8. While T cells subsets have been defined by cytokine profiles, there are important subdivisions by effector functions, in this case CD4Plac8.
Project description:The role of chlamydial proteases in the pathogenesis of Chlamydia spp. has remained largely unknown. In the present study we have generated a Chlamydia muridarum strain that is a null mutant of tail specific protease (TSP). TSP has conserved orthologs in other chlamydial species and structurally similar homologs in multiple free-living and intracellular bacteria. Similar to the roles of its homologs, TSP seems to play a crucial role in chlamydial resistance to elevated temperatures. Importantly, the tsp null mutant is also heavily attenuated in the mouse urogenital tract, indicating that TSP has a crucial role in chlamydial pathogenicity. We have utilized quantitative proteomics to identify chlamydial proteins that have altered abundances in the tsp null mutant compared to wild-type and an isogenic recombinant of the mutant. These proteins indicate potential substrates of this protease and hints toward the molecular function of TSP.