Modeling the transcriptome of genital tract epithelial cells and macrophages in healthy mucosa versus mucosa inflamed by Chlamydia muridarum infection

Problems with Understanding Chlamydia trachomatis Immunology

The pay off for understanding Chlamydia. trachomatis (CT) immunology is the development of a vaccine. Two lines of research have contributed to our current understanding of CT immunology. The first is the Grayston model of type specific immunity and genus specific pathology which was elaborated by Caldwell and Morrison as the major outer membrane protein (MOMP) and heat shock protein 60 (HSP60) paradigm. The second is the murine model of C. muridarum (CM) infection which established the essential role of major histocompatibility complex class II and CD4 T cells in immunity. However neither approach has yielded a vaccine. I review these two lines of research and conclude with six problem areas in human CT immunology whose resolution may result in a vaccine.(122 words)

Host-Pathogen Interactions of Chlamydia trachomatis in Porcine Oviduct Epithelial Cells

Chlamydia trachomatis (Ct) causes the most prevalent bacterial sexually transmitted disease leading to ectopic pregnancy and infertility. Swine not only have many similarities to humans, but they are also susceptible to Ct. Despite these benefits and the ease of access to primary tissue from this food animal, in vitro research in swine has been underutilized. This study will provide basic understanding of the Ct host–pathogen interactions in porcine oviduct epithelial cells (pOECs)—the counterparts of human Fallopian tube epithelial cells. Using NanoString technology, flow cytometry, and confocal and transmission-electron microscopy, we studied the Ct developmental cycle in pOECs, the cellular immune response, and the expression and location of the tight junction protein claudin-4. We show that Ct productively completes its developmental cycle in pOECs and induces an immune response to Ct similar to human cells: Ct mainly induced the upregulation of interferon regulated genes and T-cell attracting chemokines. Furthermore, Ct infection induced an accumulation of claudin-4 in the Ct inclusion with a coinciding reduction of membrane-bound claudin-4. Downstream effects of the reduced membrane-bound claudin-4 expression could potentially include a reduction in tight-junction expression, impaired epithelial barrier function as well as increased susceptibility to co-infections. Thereby, this study justifies the investigation of the effect of Ct on tight junctions and the mucosal epithelial barrier function. Taken together, this study demonstrates that primary pOECs represent an excellent in vitro model for research into Ct pathogenesis, cell biology and immunity.

The Role of MicroRNA-155 in Chlamydia muridarum Infected lungs

Our laboratory has investigated the role of an evolutionarily conserved RNA species called microRNAs (miRs) in regulation of anti-chlamydial protective immunity. MiRs including miR-155 expressed in specific immune effector cells are critical for antigen specific protective immunity and IFN-γ production. Using miR-155 deficient mice, and a murine pulmonary model for chlamydial infection, we report here 1) the effect of host miR-155 on bacterial burden, and 2) identify probable immune genes regulated by miR-155.

Immunobiology of monocytes and macrophages during Chlamydia trachomatis infection

Infections caused by the intracellular bacterium Chlamydia trachomatis are a global health burden affecting more than 100 million people annually causing damaging long-lasting infections. In this review, we will present and discuss important aspects of the interaction between C. trachomatis and monocytes/macrophages.

Chlamydia spp. development is differentially altered by treatment with the LpxC inhibitor LPC-011

BACKGROUND

Chlamydia species are obligate intracellular bacteria that infect a broad range of mammalian hosts. Members of related genera are pathogens of a variety of vertebrate and invertebrate species. Despite the diversity of Chlamydia, all species contain an outer membrane lipooligosaccharide (LOS) that is comprised of a genus-conserved, and genus-defining, trisaccharide 3-deoxy-D-manno-oct-2-ulosonic acid Kdo region. Recent studies with lipopolysaccharide inhibitors demonstrate that LOS is important for the C. trachomatis developmental cycle during RB- > EB differentiation. Here, we explore the effects of one of these inhibitors, LPC-011, on the developmental cycle of five chlamydial species.

RESULTS

Sensitivity to the drug varied in some of the species and was conserved between others. We observed that inhibition of LOS biosynthesis in some chlamydial species induced formation of aberrant reticulate bodies, while in other species, no change was observed to the reticulate body. However, loss of LOS production prevented completion of the chlamydial reproductive cycle in all species tested. In previous studies we found that C. trachomatis and C. caviae infection enhances MHC class I antigen presentation of a model self-peptide. We find that treatment with LPC-011 prevents enhanced host-peptide presentation induced by infection with all chlamydial-species tested.

CONCLUSIONS

The data demonstrate that LOS synthesis is necessary for production of infectious progeny and inhibition of LOS synthesis induces aberrancy in certain chlamydial species, which has important implications for the use of LOS synthesis inhibitors as potential antibiotics.