Glycointeractome of Neisseria gonorrhoeae: Identification of Host Glycans Targeted by the Gonococcus To Facilitate Adherence to Cervical and Urethral Epithelial Cells

Abstract

Neisseria gonorrhoeae is a significant threat to global health for which a vaccine and novel treatment options are urgently needed. Glycans expressed by human cells are commonly targeted by pathogens to facilitate interactions with the host, and thus characterization of these interactions can aid identification of bacterial receptors that can be exploited as vaccine and/or drug targets. Using glycan array analysis, we identified 247 specific interactions between N. gonorrhoeae and glycans representative of those found on human cells. Interactions included those with mannosylated, fucosylated, and sialylated glycans, glycosaminoglycans (GAGs), and glycans terminating with galactose (Gal), N-acetylgalactosamine (GalNAc), and N-acetylglucosamine (GlcNAc). By investigating the kinetics of interactions with selected glycans, we demonstrate that whole-cell N. gonorrhoeae has a high affinity for mannosylated glycans (dissociation constant [KD], 0.14 to 0.59 μM), which are expressed on the surface of cervical and urethral epithelial cells. Using chromatography coupled with mass spectrometric (MS) analysis, we identified potential mannose-binding proteins in N. gonorrhoeae. Pretreatment of cells with mannose-specific lectin (concanavalin A) or free mannose competitor (α-methyl-d-mannopyranoside) substantially reduced gonococcal adherence to epithelial cells. This suggests that N. gonorrhoeae targets mannosyl glycans to facilitate adherence to host cells and that mannosides or similar compounds have the potential to be used as a novel treatment option for N. gonorrhoeae. IMPORTANCE Multidrug-resistant strains of Neisseria gonorrhoeae are emerging worldwide, and novel treatment and prevention strategies are needed. Glycans are ubiquitously expressed by all human cells and can be specifically targeted by pathogens to facilitate association with host cells. Here we identify and characterize the N. gonorrhoeae host-glycan binding profile (glycointeractome), which revealed numerous interactions, including high-affinity binding to mannosyl glycans. We identify gonococcal potential mannose-binding proteins and show that N. gonorrhoeae uses mannosyl glycans expressed on the surface of cervical and urethral epithelia to facilitate adherence. Furthermore, a mannose-binding lectin or a mannoside compound was able to reduce this adherence. By characterizing the glycointeractome of N. gonorrhoeae, we were able to elucidate a novel mechanism used by this important pathogen to interact with human cells, and this interaction could be exploited to develop novel therapeutics to treat antibiotic-resistant gonorrhea.

Epidemiology, Treatments, and Vaccine Development for Antimicrobial-Resistant Neisseria gonorrhoeae: Current Strategies and Future Directions

“…Some recent developments in therapeutics have been through the enhancement of host innate immunity by interfering with N. gonorrhoeae and host cell interactions. Samchenko et al investigated the utilization of host mannosylated glycans on cervical and urethral epithelial cells by N. gonorrhoeae [ 126 , 127 ]. Pretreatment of cells with a free mannose competitor or mannose-specific lectin reduced gonococcal adherence to epithelial cells [ 126 ].…”

“…Samchenko et al investigated the utilization of host mannosylated glycans on cervical and urethral epithelial cells by N. gonorrhoeae [ 126 , 127 ]. Pretreatment of cells with a free mannose competitor or mannose-specific lectin reduced gonococcal adherence to epithelial cells [ 126 ]. Ragland et al investigated mechanisms of inhibiting lysozyme activity, identifying two proteins employed by N. gonorrhoeae in order to fully neutralize host lysozyme activity, both of which can serve as potential targets for the development of new antimicrobial therapies [ 128 ].…”

The cell surface protein MUL_3720 confers binding of the skin pathogen Mycobacterium ulcerans to sulfated glycans and keratin

“…Recently, glycan-glycan interactions have been identified as a mechanism for pathogen association with host cells [9,20,[34][35][36][37]. Surface glycans such as the lipo-oligo/polysaccharide of Gram-negative bacteria have been shown to bind to host surface glycans [9,34,35,38,39]. The extent and diversity of the glycolipids produced by mycobacterial species may thus provide another adherence factor that can explain the glycan recognition of M. ulcerans cells in the glycan array experiment.…”

Anti-Virulence Therapeutic Approaches for Neisseria gonorrhoeae

“…A study by Semchenko et al (2019) [ 190 ] used a glycan array analysis to investigate the glycan binding profile of N. gonorrhoeae and the proteins that mediate this interaction. The highest percentage of bound glycans were glycosaminoglycans, such as HSPG, and mannosylated glycans.…”