Enterococcus faecalis Gelatinase Mediates Intestinal Permeability via Protease-Activated Receptor 2

Area of Science:

• Microbiology
• Gastroenterology
• Immunology

Background:

• Microbial proteases can disrupt the intestinal epithelium, potentially leading to disease.
• Enterococcus faecalis is a colitogenic microbe that secretes proteases.

Purpose of the Study:

• To investigate the role of microbial protease-mediated disruption of the intestinal epithelium.
• To determine the specific mechanism by which Enterococcus faecalis induces epithelial permeability.
• To explore the involvement of protease-activated receptor 2 (PAR2) in this process.

Main Methods:

• Epithelial cell monolayers (Caco-2, T-84) and mouse colonic explants were exposed to Enterococcus faecalis conditioned media.
• Paracellular permeability was assessed using FITC-dextran flux.
• Experiments utilized PAR2 antagonists and PAR2-deficient mice.
• Purified gelatinase (GelE) was used to confirm protease activity.
• Fecal supernatants from ulcerative colitis patients were tested on mouse colonic epithelia.

Main Results:

• Secreted E. faecalis proteins increased epithelial permeability, an effect reduced by the absence of gelE or PAR2 blockade.
• E. faecalis-induced permeability in mouse colons was absent in PAR2-deficient mice.
• Purified GelE induced epithelial permeability and activated PAR2.
• Fecal supernatants from ulcerative colitis patients induced permeability in wild-type mouse colons, but less so in PAR2-deficient mice.

Conclusions:

• Enterococcus faecalis gelatinase (GelE) directly contributes to enteric epithelial barrier disruption.
• The mechanism involves the activation of protease-activated receptor 2 (PAR2).
• This pathway is relevant to gut diseases, including ulcerative colitis, and presents a potential therapeutic target.