Abstract
Sexually transmitted infections are a critical public health issue. However, the mechanisms underlying sexually transmitted infections in women and the link between the infection mechanism and the wide range of clinical outcomes remain elusive due to a lack of research models mimicking human infection in vivo. We established a human cervical tissue explant model to mimic local Neisseria gonorrhoeae (GC) infections. We found that GC preferentially colonize the ectocervix by activating integrin-β1, which inhibits epithelial shedding. GC selectively penetrate into the squamocolumnar junction (TZ) and endocervical epithelia by inducing β-catenin phosphorylation, which leads to E-cadherin junction disassembly. Epithelial cells in various cervical regions differentially express carcinoembryonic antigen-related cell adhesion molecules (CEACAMs), the host receptor for GC opacity-associated proteins (OpaCEA). Relatively high levels were detected on the luminal membrane of ecto/endocervical epithelial cells but very low levels intracellularly in TZ epithelial cells. CEACAM-OpaCEA interaction increased ecto/endocervical colonization and reduced endocervical penetration by increasing integrin-β1 activation and inhibiting β-catenin phosphorylation respectively, through CEACAM downstream signaling. Thus, the intrinsic properties of cervical epithelial cells and phase-variation of bacterial surface molecules both play a role in controlling GC infection mechanisms and infectivity, preferential colonization or penetration, potentially leading to asymptomatic or symptomatic infection.
Highlights
Transmitted infections (STIs) remain a challenging public health issue due, in part, to a lack of vaccines for many STI pathogens
We found that the expression of CEACAM1L but not CEACAM1S significantly increased the adherence of Pil+Opas bind to CEACAMs (OpaCEA) GC after 6-h incubation (Fig 4E and 4F)
As CEACAM1L activates the tyrosine phosphatases SHP1/2 via its immune-receptor tyrosine-based inhibitory motif (ITIM) [24, 26, 38], we examined the effect of inhibiting the enzymatic activity of SHP1/2 with a cell-permeable 7-aza-8-hydroxyquinoline compound, NSC-87877, on GC infectivity
Summary
Transmitted infections (STIs) remain a challenging public health issue due, in part, to a lack of vaccines for many STI pathogens. Gonorrhea, caused by the Gram-negative bacterium Neisseria gonorrhoeae (GC), is a common STI [1] and has reemerged as a public health crisis due to an upsurge of multidrug-resistant strains [2, 3]. How STI pathogens interact with the human female reproductive tract (FRT) and cause a wide range of clinical outcomes remains elusive. A primary obstacle for a better understanding of STIs is the lack of infection models that mimic human infection. Clinical studies suggest that GC colonization at the mucosal surface of the vagina and ectocervix leads to asymptomatic local infection [5]. The mechanism by which GC interactions with the cervical mucosal surface cause either symptomatic or asymptomatic infection remains unknown
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