Boonma, Prapaporn

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Boonma, Prapaporn
Alternative Name
Boonma, P.
Main Affiliation
Email
prapaporn.bo@kmitl.ac.th

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    Item type:Publication,
    Aging impairs protective host defenses against Clostridioides (Clostridium) difficile infection in mice by suppressing neutrophil and IL-22 mediated immunity
    (2018-12-01)
    Peniche, Alex G.
    ;
    Spinler, Jennifer K.
    ;
    Boonma, Prapaporn
    ;
    Savidge, Tor C.
    ;
    Dann, Sara M.
    Background: Morbidity and mortality associated with Clostridioides (formerly Clostridium) difficile infection (CDI) rises progressively with advanced age (≥65 years) due in part to perturbations of the gut microbiota and immune dysfunction. Epidemiological data of community-acquired CDI suggests increased susceptibility may begin earlier during middle-age (45–64 years) but the causation remains unknown. Methods: Middle-aged (12–14 months) and young (2–4 months) adult mice were infected with C. difficile, and disease severity, gut microbiome and innate immune response were compared. Cytokine reconstitution studies were performed in infected middle-aged mice. Results: Infection of middle-aged mice with C. difficile led to greater disease compared to young controls, which was associated with increases in C. difficile burden and toxin titers, and elevated bacterial translocation. With the exception of an expansion of C. difficile in middle-aged mice, microbiome analysis revealed no age-related differences. In contrast, middle-aged mice displayed a significant defect in neutrophil recruitment to the colon, with diminished levels of innate immune cytokines IL-6, IL-23 and IL-22. Importantly, recombinant IL-22 administration during CDI reduced morbidity and prevented death in middle-aged mice. Conclusion: Increased susceptibility to C. difficile occurs in middle-aged mice modeling the community-acquired CDI demographics and is driven by an impaired innate immune response.
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    Item type:Publication,
    New host-directed therapeutics for the treatment of Clostridioides difficile infection
    (2020-03-01)
    Andersson, Jourdan A.
    ;
    Peniche, Alex G.
    ;
    Galindo, Cristi L.
    ;
    Boonma, Prapaporn
    ;
    Sha, Jian
    Frequent and excessive use of antibiotics primes patients to Clostridioides difficile infection (CDI), which leads to fatal pseudomembranous colitis, with limited treatment options. In earlier reports, we used a drug repurposing strategy and identified amoxapine (an antidepressant), doxapram (a breathing stimulant), and trifluoperazine (an antipsychotic), which provided significant protection to mice against lethal infections with several pathogens, including C. difficile. However, the mechanisms of action of these drugs were not known. Here, we provide evidence that all three drugs offered protection against experimental CDI by reducing bacterial burden and toxin levels, although the drugs were neither bacteriostatic nor bactericidal in nature and had minimal impact on the composition of the microbiota. Drug-mediated protection was dependent on the presence of the microbiota, implicating its role in evoking host defenses that promoted protective immunity. By utilizing transcriptome sequencing (RNA-seq), we identified that each drug increased expression of several innate immune response-related genes, including those involved in the recruitment of neutrophils, the production of interleukin 33 (IL-33), and the IL-22 signaling pathway. The RNA-seq data on selected genes were confirmed by quantitative real-time PCR (qRT-PCR) and protein assays. Focusing on amoxapine, which had the best anti-CDI outcome, we demonstrated that neutralization of IL-33 or depletion of neutrophils resulted in loss of drug efficacy. Overall, our lead drugs promote disease alleviation and survival in the murine model through activation of IL-33 and by clearing the pathogen through host defense mechanisms that critically include an early influx of neutrophils. IMPORTANCE Clostridioides difficile is a spore-forming anaerobic bacterium and the leading cause of antibiotic-associated colitis. With few therapeutic options and high rates of disease recurrence, the need to develop new treatment options is urgent. Prior studies utilizing a repurposing approach identified three nonantibiotic Food and Drug Administration-approved drugs, amoxapine, doxapram, and trifluoperazine, with efficacy against a broad range of human pathogens; however, the protective mechanisms remained unknown. Here, we identified mechanisms leading to drug efficacy in a murine model of lethal C. difficile infection (CDI), advancing our understanding of the role of these drugs in infectious disease pathogenesis that center on host immune responses to C. difficile. Overall, these studies highlight the crucial involvement of innate immune responses, as well as the importance of immunomodulation as a potential therapeutic option to combat CDI.