Project description:Chlamydia trachomatis serovariants are responsible for either Trachoma, the leading cause of infectious blindness or sexually transmitted disease, wherein the endocervix is the most frequently infected site in women. Disease caused by Chlamydia typically involves chronic inflammation and scarring. Recent work with a live-attenuated A2497 plasmid deficient vaccine strain (A2497-) demonstrated protection in nonhuman primates against trachoma and a lack of measurable ocular pathology in A2497- infected monkeys. We therefore performed host cell transcriptome analysis of Hela cells infected with A2497 plasmid-containing (A2497) and A2497- Chlamydia over time. Our results indicate that relative to wild type A2497, the A2497- variant illicits a transcriptome response indicative of lowered inflammation response a delayed apoptosis response, a reduction in immune cell recruitement cytokine expression and a reduction in genes involved in cell proliferation and or fibrosis-like activities. The data provided here suggests a model that may explain how plasmid deficient chlamydia may provide an immuno-protective response without the pathology normally seen with plasmid-containing bacteria.
Project description:Chlamydia trachomatis serovariants are responsible for either Trachoma, the leading cause of infectious blindness or sexually transmitted disease, wherein the endocervix is the most frequently infected site in women. Disease caused by Chlamydia typically involves chronic inflammation and scarring. Recent work with a live-attenuated A2497 plasmid deficient vaccine strain (A2497-) demonstrated protection in nonhuman primates against trachoma and a lack of measurable ocular pathology in A2497- infected monkeys. We therefore performed host cell transcriptome analysis of Hela cells infected with A2497 plasmid-containing (A2497) and A2497- Chlamydia over time. Our results indicate that relative to wild type A2497, the A2497- variant illicits a transcriptome response indicative of lowered inflammation response a delayed apoptosis response, a reduction in immune cell recruitement cytokine expression and a reduction in genes involved in cell proliferation and or fibrosis-like activities. The data provided here suggests a model that may explain how plasmid deficient chlamydia may provide an immuno-protective response without the pathology normally seen with plasmid-containing bacteria. Ct infection with and without plasmid time series
Project description:To determine the role that GrgA plays in chlamydial physiology, we constructed a Chlamydia trachomatis mutant that we term L/cgad-peig, in which the chromosomal grgA (ctl0766 or ct504) has been disrupted by Targetron mutagenesis, and the plasmid carries an inducible grgA under the control of anhydrotetracycline (ATC). RNA-Seq analysis was performed for L2/cgad-peig grown with and without ATC.
Project description:Chlamydia trachomatis causes chronic inflammatory diseases of the eye and genital tract of global medical importance. The chlamydial plasmid plays an important role in the pathophysiology of these diseases as plasmid-deficient organisms are highly attenuated. The plasmid encodes both noncoding RNAs and eight conserved ORFs of undefined function. To understand plasmid gene function we generated plasmid shuttle vectors with deletions in each of the eight ORFs. The individual deletion mutants were used to transform chlamydiae and the transformants were characterized in terms of plasmid biology and transcriptional profiling. We show that pgp1-2, -6 and -8 are essential for plasmid maintenance while the other ORFs can be deleted and the plasmid stably maintained. We further show that a pgp4 knockout mutant exhibits an in vitro phenotype similar to its isogenic plasmid-less strain in terms of abnormal inclusion morphology and lack of glycogen accumulation. Microarray and qRT-PCR analysis revealed that pgp4 is involved in transcriptional regulation of multiple chromosomal genes; including the glycogen synthase gene glgA. Based on our results, we propose that Pgp1 is a plasmid replicative helicase, Pgp2 is a plasmid replication protein, Pgp4 is a transcriptional regulator of virulence associated chromosomal genes, and Pgp6-8 are plasmid partitioning proteins. These findings have important implications for understanding the plasmidM-bM-^@M-^Ys role in chlamydial pathogenesis and the development of novel antigenically multivalent live-attenuated chlamydial vaccines. Chlamydia trachomatis wild type vs. two deletion mutants, and mock
Project description:Chlamydia trachomatis causes chronic inflammatory diseases of the eye and genital tract of global medical importance. The chlamydial plasmid plays an important role in the pathophysiology of these diseases as plasmid-deficient organisms are highly attenuated. The plasmid encodes both noncoding RNAs and eight conserved ORFs of undefined function. To understand plasmid gene function we generated plasmid shuttle vectors with deletions in each of the eight ORFs. The individual deletion mutants were used to transform chlamydiae and the transformants were characterized in terms of plasmid biology and transcriptional profiling. We show that pgp1-2, -6 and -8 are essential for plasmid maintenance while the other ORFs can be deleted and the plasmid stably maintained. We further show that a pgp4 knockout mutant exhibits an in vitro phenotype similar to its isogenic plasmid-less strain in terms of abnormal inclusion morphology and lack of glycogen accumulation. Microarray and qRT-PCR analysis revealed that pgp4 is involved in transcriptional regulation of multiple chromosomal genes; including the glycogen synthase gene glgA. Based on our results, we propose that Pgp1 is a plasmid replicative helicase, Pgp2 is a plasmid replication protein, Pgp4 is a transcriptional regulator of virulence associated chromosomal genes, and Pgp6-8 are plasmid partitioning proteins. These findings have important implications for understanding the plasmid’s role in chlamydial pathogenesis and the development of novel antigenically multivalent live-attenuated chlamydial vaccines.
Project description:The T cell response to Chlamydia genital tract infections in humans and mice is unusual in that the majority of antigen-specific CD8 T cells are not restricted by HLA/MHC class I and therefore have been referred to as “unrestricted” or “atypical”. We previously reported that a subset of unrestricted murine Chlamydia-specific CD8 T cells had an unusual cytokine polarization pattern that included IFN-ɣ and IL-13. For this report, we investigated the transcriptome of Chlamydia-specific CD8ɣ13 T cells, comparing them to Chlamydia-specific multifunctional Tc1 clones using gene expression micro array analysis. The molecular study revealed that CD8ɣ13 polarization included IL-5 in addition to IFN-γ and IL-13. Adoptive transfer studies were performed with Tc1 clone and CD8ɣ13 T cell clones to determine whether either influenced bacterial clearance or immunopathology during Chlamydia muridarum (Cm) genital tract infections. To our surprise, an adoptively transferred CD8ɣ13 T cell clone was remarkably proficient at preventing chlamydia immunopathology while the multifunctional Tc1 clone did not enhance clearance or significantly protect from immunopathology. Mapping studies with MHC class I- and class II-deficient splenocytes showed our previously published Chlamydia-specific CD8 T cell clones are MHC class II-restricted. MHC class II-restricted CD8 T cells may play important roles in protection from intracellular pathogens that limit class I antigen presentation or deplete the CD4 T cell compartment.
Project description:We applied Formaldehyde-Assisted Isolation of Regulatory Elements enrichment followed by sequencing (FAIRE-Seq) to generate genome-wide temporal chromatin maps of Chlamydia trachomatis-infected human epithelial cells in vitro over the chlamydial developmental cycle. We detected both conserved and distinct temporal regions of chromatin accessibility associated with C. trachomatis infection. The observed differentially accessible chromatin regions, including several Clusters of Open Regulatory Elements (COREs) and temporally-enriched sets of transcription factors, may help shape the host cell response to infection. These regions and motifs were linked to genomic features and genes associated with immune responses, re-direction of host cell nutrients, intracellular signaling, cell-cell adhesion, extracellular matrix, metabolism and apoptosis. This work will serve as a basis for future functional studies of transcriptional regulation and epigenomic regulatory elements in Chlamydia-infected human cells.
Project description:Transcriptional profiling of human epithelial cell line (HL) infected with Chlamydia penumoniae compared to control cells at time points 12h, 24h, 48h, 72h after the infection. Keywords: Chlamydia peneumoniae infection
Project description:Chlamydia trachomatis is an obligate intracellular pathogen that causes trachoma and sextually transmitted disease in human. During early stage of infection, Chlamydia secreted bacterial effector proteins into host cell cytoplasm to help its entry and estabilishment of early replicated niche. We identified a Chlamydia mutant that lack an early Effector. To address the function of this effector, we infected A2EN cells with this mutant (G1V) and its complemented counterpart (G1TEPP) to see what host gene transcriptions are affected by this effector. A2EN cells were mock infected, or infected with a Chlamydia mutant or its complemented counterpart for 4 hour post infection.
Project description:The overall study examines the mechanism and role of innate re-stimulation of T cells after activation and differentiation during infection. This particular study is focused on the restimulation of Th1 cells activated during Chlamydia infection, using in vivo LPS stimulation to increase the response. The study was conducted to compare the expression profile after LPS stimulation during Chlamydia infection to that seen after LPS stimulation during Salmonella infection (submitted as a separate dataset).