Biology subjects

Pelayo, P.

Publications and source records attributed to Pelayo, P..

3 recordsLinked to original sources

bioRxiv2024

Prevotella timonensis degrades the vaginal epithelial glycocalyx through high fucosidase and sialidase activities

Bacterial vaginosis (BV) is a polymicrobial infection of the female reproductive tract (FRT). BV is characterized by replacement of health-associated Lactobacillus species by diverse anaerobic bacteria, including the well-known Gardnerella vaginalis. Prevotella timonensis and Prevotella bivia are anaerobes that are found in a significant percentage of BV patients, but their pathogenic properties are yet to be determined. Defining characteristics of anaerobic overgrowth in BV are adherence to the mucosal surface and the increased activity of mucin-degrading enzymes such as sialidases in vaginal secretions. Here, we demonstrate that P. timonensis but not P. bivia strongly adhered to vaginal and endocervical cells to a similar level as G. vaginalis but did not elicit a comparable pro-inflammatory response. The P. timonensis genome uniquely encodes a large set of mucus-degrading enzymes including 4 putative fucosidases and 2 putative sialidases, PtNanH1 and PtNanH2. Enzyme assays demonstrated that fucosidase and sialidase activity in P. timonensis cell-bound and secreted fractions was significantly higher than for other vaginal anaerobes. Infection assays revealed that P. timonensis fucosidases and sialidases efficiently removed fucose and 2,3- and 2,6-linked sialic acid moieties from the epithelial glycocalyx. Recombinantly expressed P. timonensis NanH1 and NanH2 efficiently removed 2,3 and 2,6-linked sialic acids from the epithelial surface and sialic acid removal by P. timonensis could be blocked using inhibitors. This study demonstrates that P. timonensis has distinct virulence properties that include initial adhesion and a high capacity for mucin degradation at the vaginal epithelial mucosal surface. Our results underline the importance of understanding the role of different anaerobic bacteria in BV. Significance statement (Layman)Bacterial vaginosis (BV) is a common vaginal infection that affects a high percentage of women and is associated with reduced fertility and increased risk of secondary infections. Gardnerella vaginalis is the most well-known BV-associated bacterium, but Prevotella species including P. timonensis and P. bivia may also play an important role. We showed that, similar to G. vaginalis, P. timonensis adhered well to the vaginal epithelium, suggesting that both bacteria could be important in the first stage of infection. Compared to the other bacteria, P. timonensis was unique in efficiently removing the protective mucin sugars that cover the vaginal epithelium. These results underscore that vaginal bacteria play different roles in the initiation and development of BV.

microbiology↗

bioRxiv2024

Prevotella are major contributors of sialidases in the human vaginal microbiome.

Elevated bacterial sialidase activity in the female genital tract is strongly associated with poor health outcomes including preterm birth and bacterial vaginosis. These negative effects may arise from sialidase-mediated degradation of the protective mucus layer in the cervicovaginal environment. Prior biochemical studies of vaginal bacterial sialidases have focused solely on the bacterial vaginosis-associated organism Gardnerella vaginalis. Despite their implications for sexual and reproductive health, sialidases from other vaginal bacteria have not been characterized. Here, we show that vaginal Prevotella species produce active sialidases that possess variable activity toward mucin. These sialidases are highly conserved across clades of Prevotella from different geographies, hinting at their importance globally. Finally, we find that Prevotella sialidases, including mucin-degrading enzymes from Prevotella timonensis, are highly prevalent and abundant in human vaginal metagenomes and metatranscriptomes, Together, our results identify Prevotella as a critical source of sialidases in the vaginal microbiome, improving our understanding of this detrimental bacterial activity. Significance StatementSialidase activity in the vaginal microbiome is increased in bacterial vaginosis and strongly associated with other adverse health outcomes. Sialidase enzymes release sialic acid from host-derived glycans in the vaginal environment, altering their structures and functions. However, biochemical studies of vaginal bacterial sialidases have been limited to one genus, Gardnerella. In this work, we identify and characterize multiple active sialidase enzymes in vaginal bacteria of the genus Prevotella. We find that Prevotella sialidases are more prevalent and abundant in vaginal microbial communities than Gardnerella sialidases. Our work highlights Prevotella bacteria as an underappreciated source of sialidase activity with important implications for both our understanding of vaginal health and therapeutic development.

microbiology↗

bioRxiv2022

FAP106 is an interaction hub required for stable assembly of conserved and lineage-specific proteins at the cilium inner junction

Motility of pathogenic protozoa depends on flagella (synonymous with cilia) with axonemes containing nine doublet microtubules (DMTs) and two singlet microtubules. Microtubule inner proteins (MIPs) within DMTs influence axoneme stability and motility and provide lineage-specific adaptations, but individual MIP functions and assembly mechanisms are mostly unknown. Here, we show in the sleeping sickness parasite Trypanosoma brucei, that FAP106, a conserved MIP at the DMT inner junction, is required for trypanosome motility and functions as a critical interaction hub, directing assembly of several conserved and lineage-specific MIPs. We further use comparative cryogenic electron tomography (cryoET) and quantitative proteomics to identify novel MIP candidates, and RNAi knockdown plus fitting of AlphaFold models into cryoET maps to demonstrate one of these, MC8, is a trypanosome-specific MIP required for parasite motility. Our work advances understanding of MIP assembly mechanisms and identifies lineage-specific motility proteins that are attractive targets to consider for therapeutic intervention.

cell biology↗