Project description:Chlamydiae are obligate intracellular bacteria comprising well-known human pathogens and ubiquitous symbionts of protists, which are characterized by a unique developmental cycle. Here we comprehensively analyzed gene expression dynamics of Protochlamydia amoebophila during infection of its Acanthamoeba host by RNA sequencing. This revealed a highly dynamic transcriptional landscape, where major transcriptional shifts are conserved among chlamydial symbionts and pathogens. Our data served to propose a time-resolved model for type III protein secretion during the developmental cycle, and we provide evidence for a biphasic metabolism of P. amoebophila during infection, which involves energy parasitism and amino acids as carbon source during initial stages and a post-replicative switch to endogenous glucose-based ATP production. This fits well with major transcriptional changes in the amoeba host, where upregulation of complex sugar breakdown precedes the P. amoebophila metabolic switch. The biphasic chlamydial metabolism represents a unique adaptation to exploit eukaryotic host cells, which likely contributed to the evolutionary success of this group of microbes.
Project description:The goal of this study was to use heterologous microarray hybridization to determine genomic content shared among different vesicomyid symbionts. These symbionts are closely related and can be thought of as different strains of bacteria, facilitating the use of heterologous microarray hybridization to determine genomic content. Keywords: comparative genomic hybridization
Project description:The goal of this study was to use heterologous microarray hybridization to determine genomic content shared among different vesicomyid symbionts. These symbionts are closely related and can be thought of as different strains of bacteria, facilitating the use of heterologous microarray hybridization to determine genomic content. Keywords: comparative genomic hybridization Microarrays were built off the Ruthia magnifica genome and two replicate hybridizations to this organism were used as a baseline for comparisons. Genomic DNA from two other vesicomyid symbionts (Calyptogena kilmeri and C. pacifica symbionts) was also hybridized to the array with three biological replicates for each sample.
Project description:NK cells and pulmonary macrophages both are important components of innate immunity. The interaction between NK cells and pulmonary macrophages during Chlamydia muridarum(C. muridarum)respiratory infections is poorly understood. In this study, we explored the effect of NK cells on regulation of pulmonary macrophage function during chlamydial lung infection. We found that NK depletion led to polarization of pulmonary macrophages from M1 to M2 phenotype, and this related to significantly reduced miR-155 expression in pulmonary macrophage. Using adoptive transfer approach, we found that the recipient mice receiving lung macrophages isolated from C. muridarum-infected NK-cell-depleted mice exhibited an increased bacterial load and severe inflammation in the lung upon chlamydial challenge when compared with the recipients of lung macrophages from infected IgG -treated mice. Herein, the effects of NK cells on macrophage polarization were examined in vitro. We found that NK cells from chlamydial-infected mice (iNK) significantly induced M1 polarization compared to that from sham-infected mice (uNK). Inhibition of miR-155 expression in macrophages attenuated M1 polarization induced by iNK, while miR-155 over-expression enhanced it. Furthermore, neutralization of IFN-γ in the coculture system decreased the expression of miR-155 by macrophages, and resulted in diminished M1 polarization induced by iNK cells. The data indicates that NK cells direct M1 polarization through up-regulation of miR-155 by IFN-γ production, and NK-regulated macrophage polarization is functionally relevant to host defense against chlamydial infection.
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:Chlamydia trachomatis (C. trachomatis) is a major etiological agent of sexually transmitted infection. Some stressing conditions can result in persistent chlamydial infection, which is thought to associate with severe complications such as ectopic pregnancy and tubal factor infertility. Long noncoding RNAs (lncRNAs) have been identified as key modulators in many biological processes. However, the role of lncRNAs in persistent chlamydial infection is still unclear. In this study, we used lncRNA and mRNA microarray to identify the global lncRNAs and mRNAs expression in penicillin-induced persistent chlamydial infection in HeLa cells as well as the control group (HeLa cells without C. trachomatis infection). Among 1005 differentially expressed lncRNAs, 585 lncRNAs were upregulated and 420 downregulated in persistent chlamydial infection, while 410 mRNAs were identified to express differentially, of which 113 mRNAs were upregulated and 297 downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis with differentially expressed genes were performed. We then constructed the lncRNA-miRNA-mRNA competing endogenous RNAs (ceRNAs) network. Four mRNAs were validated to be changed by quantitative real-time PCR which were correlated with the microarray result. Integration of protein-protein interaction (PPI) network was constructed and hub genes were identified. These findings provide a new perspective on the molecular mechanism of penicillin-induced persistent chlamydial infection.
Project description:Host-microbe interactions are virtually bidirectional, benefiting both the host and microbial sides. It is becoming increasingly recognized the influence of the microbe on many aspects of host physiology and diseases, but whether/how the host affects their symbionts is poorly characterized. Here, we reported that the host acts as a critical factor to shape the lifestyle of their symbionts in the Drosophila and bacteria model system. First, we observe that Drosophila larvae play a pivotal role in competing with pathogenic symbionts in the co-existing niche. More specifically, host larvae antagonize symbionts by deconstructing the surface slick, preventing outgrowth and antagonizing the pathogenicity of S. marcescens. Furthermore, Drosophila larvae cause the shift in the transcriptomic profile of S. marcescens, characterized with the upregulated expression of genes related to bacterial proliferation and growth and the downregulated expression of genes related to bacterial pathogenicity. More importantly, advances in bacterial single-cell RNA sequencing provide opportunities to reveal transcriptional variation, including toxic factors, across individual cells and a subpopulation clustering of isogenic bacterial populations. Finally, we found that AMPs from larvae recapitulated the response of S. marcescens to the presence of Drosophila larvae. Altogether, these findings provide an insight into the pivotal roles of the host in influencing the potential pathogens' lifecycle switching from commensalism to pathogenicity, opening the door to a better understanding of the ecological relationships between the host and microbe.
Project description:Host-microbe interactions are virtually bidirectional, benefiting both the host and microbial sides. It is becoming increasingly recognized the influence of the microbe on many aspects of host physiology and diseases, but whether/how the host affects their symbionts is poorly characterized. Here, we reported that the host acts as a critical factor to shape the lifestyle of their symbionts in the Drosophila and bacteria model system. First, we observe that Drosophila larvae play a pivotal role in competing with pathogenic symbionts in the co-existing niche. More specifically, host larvae antagonize symbionts by deconstructing the surface slick, preventing outgrowth and antagonizing the pathogenicity of S. marcescens. Furthermore, Drosophila larvae cause the shift in the transcriptomic profile of S. marcescens, characterized with the upregulated expression of genes related to bacterial proliferation and growth and the downregulated expression of genes related to bacterial pathogenicity. More importantly, advances in bacterial single-cell RNA sequencing provide opportunities to reveal transcriptional variation, including toxic factors, across individual cells and a subpopulation clustering of isogenic bacterial populations. Finally, we found that AMPs from larvae recapitulated the response of S. marcescens to the presence of Drosophila larvae. Altogether, these findings provide an insight into the pivotal roles of the host in influencing the potential pathogens' lifecycle switching from commensalism to pathogenicity, opening the door to a better understanding of the ecological relationships between the host and microbe.
Project description:The phylum Chlamydiae consists of obligate intracellular bacteria including major human pathogens and diverse environmental representatives. Here we investigated the Rhabdochlamydiaceae, which is predicted to be the largest and most diverse chlamydial family, with the few described members known to infect arthropod hosts. Using published 16 S rRNA gene sequence data we identified at least 388 genus-level lineages containing about 14 051 putative species within this family. We show that rhabdochlamydiae are mainly found in freshwater and soil environments, suggesting the existence of diverse, yet unknown hosts. Next, we used a comprehensive genome dataset including metagenome assembled genomes classified as members of the family Rhabdochlamydiaceae, and we added novel complete genome sequences of Rhabdochlamydia porcellionis infecting the woodlouse Porcellio scaber, and of 'Candidatus R. oedothoracis' associated with the linyphiid dwarf spider Oedothorax gibbosus. Comparative analysis of basic genome features and gene content with reference genomes of well-studied chlamydial families with known host ranges, namely Parachlamydiaceae (protist hosts) and Chlamydiaceae (human and other vertebrate hosts) suggested distinct niches for members of the Rhabdochlamydiaceae. We propose that members of the family represent intermediate stages of adaptation of chlamydiae from protists to vertebrate hosts. Within the genus Rhabdochlamydia, pronounced genome size reduction could be observed (1.49-1.93 Mb). The abundance and genomic distribution of transposases suggests transposable element expansion and subsequent gene inactivation as a mechanism of genome streamlining during adaptation to new hosts. This type of genome reduction has never been described before for any member of the phylum Chlamydiae. This study provides new insights into the molecular ecology, genomic diversity, and evolution of representatives of one of the most divergent chlamydial families.