Neisseria gonorrhoeae central metabolism in the context of neutrophilic inflammation

摘要

ABSTRACT Neisseria gonorrhoeae (Gc) is the causative agent of the sexually transmitted disease gonorrhea. Gc is a prominent threat to human health due to emergence of “superbug” strains that are resistant to all current antibiotics and its clinical sequelae, including infertility and chronic pelvic pain, that have severe and lifelong effects. Gc is highly adapted to colonize human mucosal surfaces, where it survives despite initiating a robust inflammatory response and influx of polymorphonuclear leukocytes (PMNs or neutrophils) that typically clear bacteria. We recently used the unbiased, genome-wide approaches of transposon-sequencing and dual RNA- sequencing of Gc and PMNs to identify a cohort of genes contributing to successful Gc infection of PMNs. Gc metabolic genes were overrepresented in this cohort, suggesting that Gc utilizes distinct metabolic pathways to circumvent human mucosal defenses. We have applied this information to systems biology approaches to generate a preliminary metabolic network reconstruction for Gc. This analysis leads to the prediction that Gc utilizes specific host-derived metabolites to fuel its metabolism – in particular, lactate. PMNs are highly glycolytic and consequently secrete lactate. Lactate can be consumed by Gc and is known to stimulate Gc glycolysis. Thus we hypothesize that Gc exploits PMN metabolism, specifically lactate secretion, to survive at mucosal surfaces. In this proposal, we will identify the central carbon metabolic pathways used by Gc in the presence of neutrophils, using a combination of metabolite analysis, metabolic modeling, and bacterial genetic knockouts in Gc metabolic enzymes. We will then test the necessity of these metabolic pathways in Gc for enhancing bacterial survival from neutrophils and the underlying mechanisms, including modulating neutrophil antimicrobial responses, changing Gc sensitivity to neutrophil antimicrobial components, and/or circumventing host nutritional immunity, or modulating neutrophil antimicrobial responses. Together, this proposal will address key gaps in knowledge of the fundamental metabolic processes of Gc during infection that are likely to have major impacts on outcomes of gonorrhea.