Campylobacter fetus translocation across Caco-2 cell monolayers

Area of Science:

• Microbiology
• Cell Biology
• Infectious Diseases

Background:

• Campylobacter fetus is a pathogen affecting humans and animals, with transmission often linked to contaminated food or water.
• Its presence in systemic locations suggests an ability to cross intestinal epithelial barriers.

Purpose of the Study:

• To investigate the mechanism by which Campylobacter fetus disseminates from the intestine across epithelial barriers.
• To determine if C. fetus invades and translocates through intestinal cells.

Main Methods:

• Utilized Caco-2 cell monolayers as a model for intestinal epithelium.
• Employed antibiotic protection assays and electron microscopy to observe invasion and translocation.
• Assessed monolayer integrity using transepithelial electrical resistance and FITC-inulin permeability.
• Investigated the role of the cytoskeleton using agents like latrunculin A, cytochalasin D, colchicine, and vinblastine.

Main Results:

• Campylobacter fetus translocated across Caco-2 cell monolayers in both directions without compromising barrier integrity.
• The bacterium invaded and egressed from Caco-2 cells independently of its S layer expression.
• Electron microscopy confirmed intracellular C. fetus but not in paracellular spaces or associated with cell junctions.
• Translocation was not affected by latrunculin A but enhanced by cytochalasin D; it was inhibited by tubulin cytoskeleton disruptors (colchicine, vinblastine).

Conclusions:

• Campylobacter fetus utilizes a transcellular route for translocation across intestinal epithelial barriers.
• This mechanism involves invasion and subsequent egress from host cells, facilitated by a functional tubulin cytoskeleton.
• The ability to translocate and invade contributes to the pathogen's systemic dissemination and establishment in hosts.