Browsing by Author "Ryan, John D."

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    24435 Pathogen-specific metabolic pathways and innate immune responses associated with Chlamydia trachomatis infection and other STIs
    (Cambridge University Press, 2021) Ryan, John D.; Toh, Evelyn; Brothwell, Julie A.; Sun, Yuan; Jordan, Stephen J.; Nelson, David E.; Microbiology and Immunology, School of Medicine
    ABSTRACT IMPACT: This project seeks to identify unique host responses that are biomarkers for specific urethral pathogens, and which can be used in the development of point-of-care (POC) STI diagnostics. OBJECTIVES/GOALS: How Chlamydia trachomatis (CT) and other common STIs, e.g. Neisseria gonorrhoeae, evade immunity and elicit pathology in the male urethra is poorly understood. Our objective is to determine how STI-infected urethral epithelial cells, as well as the uninfected ‘bystander’ cells with which infected cells communicate, respond to CT and other STIs. METHODS/STUDY POPULATION: We evaluated how immortalized urethral cell lines - including transduced human urethral epithelial cells (THUECs) - respond to increasing doses of CT infectious particles using in vitro one-step progeny assays performed in the presence or absence of cycloheximide, a drug that inhibits eukaryotic protein synthesis. We will perform concurrent single-cell RNA sequencing (scRNA-seq) and multiplex cytokine analyses to determine how different CT doses impact the transcriptomes of infected and bystander urethral epithelial cells and modulate cytokine production of the overall monolayer. Results of these experiments will inform the feasibility of performing similar analyses in situ using urethral swabs from men with clinically diagnosed urethritis. RESULTS/ANTICIPATED RESULTS: Our results demonstrate that immune-competent urethral cell monolayers strongly resist CT infection, unless most of the cells are simultaneously infected. This suggests that uninfected bystander cells sense CT-infected cells and secrete soluble factors that may act to limit CT proliferation in infected cells and to inform remaining uninfected cells that a potential pathogen is present. We anticipate that our scRNA-seq and cytokine analyses will identify both specific effector pathways that protect against CT and intracellular signals that modulate them. We speculate that these pathways and signals may differ during infection with CT and other STIs. Importantly, we anticipate that our in vitro model of CT infection will be highly representative of in situ immune responses observed in urethras of infected men. DISCUSSION/SIGNIFICANCE OF FINDINGS: In men, common STIs including CT are usually managed syndromically due to a lack of POC diagnostics. By determining how STIs elicit urethral inflammation and identifying countermeasures that STIs use to evade urethral immunity, we can identify host responses that serve as biomarkers for urethritis, generally, and for specific urethral pathogens.
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    The Detection and Analysis of Pathogen-Reactive Immunoglobulins in the Urine of Men With Nongonococcal Urethritis
    (2023-05) Ryan, John D.; Nelson, David E.; Jordan, Stephen J.; Kaplan, Mark H.; Absalon, Sabrina
    Inflammation of the urethra—urethritis—is commonly diagnosed in men and women who have sexually transmitted infections (STI). Characteristic signs and symptoms of urethritis include urethral discharge and burning pain during urination (dysuria). However, these findings are non-specific and can be elicited by STI for which optimal treatment approaches differ. We wanted to investigate if immunoglobulins (antibodies) in the urine of men with acute urethritis could determine the etiologies of these cases. Previously, we conducted an observational case-control study of biological males to compare the urethral microbiota of participants with unambiguous, laboratory-confirmed urethritis (cases) and participants without urethral inflammation (controls). This revealed that nearly 2 in 5 men with nongonococcal urethritis tested negative for all common STI. We identified atypical urethral pathogens in approximately 1/3 of these STI-negative individuals using shotgun metagenomic sequencing. However, we did not detect microorganisms suspected to be urethral pathogens in the remaining 2/3 of STI-negative participants. We hypothesized that these men with “pathogen-negative” urethritis had persisting inflammation from a recent STI that already cleared spontaneously by the time of testing. We observed that urine IgA antibodies against Chlamydia trachomatis (Ctr) infectious particles were significantly more prevalent among men with pathogen-negative urethritis compared to controls. In contrast, we found that the prevalence of urine anti-Ctr IgA was similar between controls and urethritis cases with atypical infections. However, our efforts to detect antibodies against another common STI, Mycoplasma genitalium (Mgen), were complicated by low abundance in urine and the unexpected prevalence of Mgen-reactive antibodies among controls. Collectively, our results suggest that signs and symptoms of urethritis can continue after the causative STI(s) have been eliminated. Furthermore, male urine represents a practical, non-invasive source of pathogen-reactive antibodies that could be evaluated using point-of-care diagnostic tests to elucidate urethritis etiologies. Importantly, our results also suggest that sexual partners of men with pathogen-negative, nongonococcal urethritis are an unrecognized chlamydia reservoir.
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    No Pathogen-Specific Sign or Symptom Predicts the Etiology of Monomicrobial Nongonococcal Urethritis in Men
    (Wolters Kluwer, 2020-05) Jordan, Stephen J.; Toh, Evelyn; Williams, James A.; Fortenberry, Lora; LaPradd, Michelle; Ryan, John D.; Nelson, David E.; Batteiger, Teresa A.; Medicine, School of Medicine
    Identifying pathogen-specific signs or symptoms of nongonococcal urethritis could improve syndromic management accuracy. We evaluated nongonococcal urethritis signs and symptoms in 220 men with single-pathogen infections (Chlamydia trachomatis, Mycoplasma genitalium, Trichomonas vaginalis, or Ureaplasma urealyticum) or idiopathic urethritis. No individual sign or symptom accurately predicted the infectious etiology.
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    A Same-Genus Screening Approach Reveals Novel Effectors and New Possibilities for Investigating Chlamydia Pathogenesis
    (American Society for Microbiology, 2021-06) Ryan, John D.; Nelson, David E.; Microbiology and Immunology, School of Medicine
    Chlamydiae are obligate intracellular pathogens that rely on secreted effector proteins to establish their intracellular niche. In this issue of the Journal of Bacteriology, Yanatori et al describe a screen for C. pneumoniae effectors, performed in C. trachomatis, which identified several new proteins that are translocated during infection (Yanatori, Miura et al. 2021). More broadly, they demonstrate how new genetic approaches in C. trachomatis can be used to characterize the virulence factors of other Chlamydia species.