Protease activities of vaginal Porphyromonas species disrupt coagulation and extracellular matrix in the cervicovaginal niche

Abstract

Porphyromonas asaccharolytica and Porphyromonas uenonis are common inhabitants of the vaginal microbiome, but their presence has been linked to adverse health outcomes for women, including bacterial vaginosis and preterm birth. However, little is known about the pathogenesis mechanisms of these bacteria. The related oral opportunistic pathogen, Porphyromonas gingivalis, is comparatively well-studied and known to secrete numerous extracellular matrix-targeting proteases. Among these are the gingipain family of cysteine proteases that drive periodontal disease progression and hematogenic transmission to the placenta. In this study, we demonstrate that vaginal Porphyromonas species secrete broad-acting proteases capable of freely diffusing within the cervicovaginal niche. These proteases degrade collagens that are enriched within the cervix (type I) and chorioamniotic membranes (type IV), as well as fibrinogen, which inhibits clot formation. Bioinformatic queries confirmed the absence of gingipain orthologs and identified five serine, cysteine, and metalloprotease candidates in each species. Inhibition assays revealed that each species’ proteolytic activity can be partially attributed to a secreted metalloprotease with broad substrate specificity that is distantly related to the P. gingivalis endopeptidase PepO. This characterization of virulence activities in vaginal Porphyromonas species highlights their potential to alter the homeostasis of reproductive tissues and harm human pregnancy through clotting disruption, fetal membrane weakening, and premature cervical remodeling.

C10Pred: A First Machine Learning Based Tool to Predict C10 Family Cysteine Peptidases Using Sequence-Derived Features

“…S. pyogenes expresses a highly conserved virulence factor streptopain (a C10 family cysteine peptidase) known to degrade an array of GAS and host proteins [ 44 ]. Although much of the work on this C10 cysteine protease has been reported from Streptococcal strains, many recent studies have identified this protease or its homologs in other bacterial species [ 34 , 35 , 45 , 46 ]. The biological activities and molecular functions of proteins can be predicted from their amino acid sequences [ 47 ].…”

Advances in mass spectrometry technologies to characterize cervicovaginal microbiome functions that impact spontaneous preterm birth

“…109 Proteases also have the potential to weaken cervical function and other host defences against sPTB. 110,111 Several host protease inhibitors (such as cystatin A, inter-alpha-trypsin inhibitor and serine protease inhibitor Kazal-type 5) were found to be associated with optimal Lactobacillus dominant microbiomes in a metaproteomics study. 112 One of the proteins identified in this study, cystatin A, was found to decrease towards the onset of labour in another study by Heng et al 113 Furthermore, secretory leukocyte protease inhibitor, which has a protective and anti-inflammatory role in the genital tract, 114 is decreased in women with STIs or BV 115 and has been found to be associated with lower risk of sPTB when present at high levels.…”

“…There is recent evidence that human proteases, a broad group of enzymes that can modify protein products and function by breaking down polypeptides, 108 may increase the inflammatory response elicited by less‐optimal microbiota (such as L. iners ), which in turn could increase the risk of sPTB 109 . Proteases also have the potential to weaken cervical function and other host defences against sPTB 110,111 . Several host protease inhibitors (such as cystatin A, inter‐alpha‐trypsin inhibitor and serine protease inhibitor Kazal‐type 5) were found to be associated with optimal Lactobacillus dominant microbiomes in a metaproteomics study 112 .…”

Microenvironment of the Lower Reproductive Tract: Focus on the Cervical Mucus Plug

“…This characterization of virulence activities in vaginal Porphyromonas species highlights their potential to alter the homeostasis of reproductive tissues and harm pregnancy through clotting disruption, fetal membrane weakening, and premature cervical remodeling. 48 In addition to its protective function, changes in the properties of the CMP have been linked to an elevated risk of preterm birth. 19 Therefore, understanding the intricate interplay between the lower reproductive tract microbiota, CMP, and mechanisms of infection ascent is crucial for unraveling the complex dynamics that contribute to preterm birth risk and developing potential preventive strategies.…”