Interferon-γ Possesses Anti-Microbial and Immunomodulatory Activity on a Chlamydia Trachomatis Infection Model of Primary Human Synovial Fibroblasts

Coexpression Network Analysis-Based Identification of Critical Genes Differentiating between Latent and Active Tuberculosis

Methods

Three Gene Expression Omnibus (GEO) microarray datasets (GSE19491, GSE98461, and GSE152532) were downloaded, with GSE19491 and GSE98461 then being merged to form a training dataset. Hub genes capable of differentiating between ATB and LTBI were then identified through differential expression analyses and a WGCNA analysis of this training dataset. Receiver operating characteristic (ROC) curves were then used to gauge to the diagnostic accuracy of these hub genes in the test dataset (GSE152532). Gene expression-based immune cell infiltration and the relationship between such infiltration and hub gene expression were further assessed via a single-sample gene set enrichment analysis (ssGSEA).

Results

In total, 485 differentially expressed genes were analyzed, with the WGCNA approach yielding 8 coexpression models. Of these, the black module was the most closely correlated with ATB. In total, five hub genes (FBXO6, ATF3, GBP1, GBP4, and GBP5) were identified as potential biomarkers associated with LTBI progression to ATB based on a combination of differential expression and LASSO analyses. The area under the ROC curve values for these five genes ranged from 0.8 to 0.9 in the test dataset, and ssGSEA revealed the expression of these genes to be negatively correlated with lymphocyte activity but positively correlated with myeloid and inflammatory cell activity.

Conclusion

The five hub genes identified in this study may play a novel role in tuberculosis-related immunopathology and offer value as novel biomarkers differentiating LTBI from ATB.

Better In Vitro Tools for Exploring Chlamydia trachomatis Pathogenesis

Currently, Chlamydia trachomatis still possesses a significant impact on public health, with more than 130 million new cases each year, alongside a high prevalence of asymptomatic infections (approximately 80% in women and 50% in men). C. trachomatis infection involves a wide range of different cell types, from cervical epithelial cells, testicular Sertoli cells to Synovial cells, leading to a broad spectrum of pathologies of varying severity both in women and in men. Several two-dimensional in vitro cellular models have been employed for investigating C. trachomatis host–cell interaction, although they present several limitations, such as the inability to mimic the complex and dynamically changing structure of in vivo human host-tissues. Here, we present a brief overview of the most cutting-edge three-dimensional cell-culture models that mimic the pathophysiology of in vivo human tissues and organs for better translating experimental findings into a clinical setting. Future perspectives in the field of C. trachomatis research are also provided.

Towards a Deeper Understanding of Chlamydia trachomatis Pathogenetic Mechanisms: Editorial to the Special Issue "Chlamydia trachomatis Pathogenicity and Disease"

Chlamydia trachomatis, an obligate intracellular Gram-negative bacterium, is characterized by a wide range of different serotypes responsible for several local or systemic human diseases, including genital tract manifestations (D-K), trachoma (A-C), and lymphogranuloma venereum (L1-3) [...].

In Vitro Modelling of Chlamydia trachomatis Infection in the Etiopathogenesis of Male Infertility and Reactive Arthritis

Chlamydia trachomatis is an obligate, intracellular bacterium responsible for a range of diseases of public health importance, since C. trachomatis infection is often asymptomatic and, hence, untreated, leading to chronic complications, including prostatitis, infertility, and reactive arthritis. The ample spectrum of diseases caused by C. trachomatis infection is reflected in its ability to infect and multiply within a wide range of different cell types. Cervical epithelial cells, to date, have been the most studied cellular infection model, highlighting the peculiar features of the host-cell inflammatory and immune responses to the infection. Herein, we provide the up-to-date evidence on the interaction between C. trachomatis and human prostate epithelial, Sertoli and synovial cells.

Potential IFNγ Modulation of Inflammasome Pathway in Chlamydia trachomatis Infected Synovial Cells

Following a Chlamydia trachomatis infection, the host immune response is characterized by its recognition via Toll-like and Nod-like Receptors, and the subsequent activation of interferon (IFN)-γ-mediated signaling pathways. Recently, the inflammasome-mediated host cell response has emerged to play a role in the physiopathology of C. trachomatis infection. Here we investigated, for the first time, the interaction of IFN-γ and inflammasome in an in vitro model of C. trachomatis-infected primary human synovial cells. Chlamydial replication as well as the expression of caspase-1, IL-1β, as well as IL-18 and IL-6, were assayed. Our results demonstrated the inhibitory activity of IFN-γ by interfering with the inflammasome network through the downregulation of caspase-1 mRNA expression. In addition, the ability of C. trachomatis to hinder the inflammasome pathway favoring its intracellular survival within synovial cells, was observed. Overall, our data suggest a potential mechanism of immune evasion by C. trachomatis in synovial cells, that may be contested by IFN-γ.