Desmosomes are unaltered during infections by attaching and effacing pathogens

Area of Science:

• Microbiology
• Cell Biology
• Pathogenesis

Background:

• Attaching and effacing (A/E) intestinal pathogens like EHEC, EPEC, and Citrobacter rodentium cause significant diarrhea.
• These bacteria extensively modify host cell components, including the cytoskeleton and tight junctions.
• Cytokeratin-18, an intermediate filament protein, is notably altered during enteropathogenic E. coli (EPEC) infections.

Purpose of the Study:

• To investigate whether desmosomes, intercellular junctions linked to intermediate filaments, are affected by A/E pathogen infections.
• To determine the impact of A/E pathogenesis on desmosomal protein levels, localization, and morphology.

Main Methods:

• In vitro infection models using EPEC.
• In vivo infection models using Citrobacter rodentium in mice.
• Immunofluorescence microscopy to assess protein localization.
• Electron microscopy to analyze desmosome structure.

Main Results:

• Desmosomal transmembrane proteins (desmoglein, desmocollin) and plaque protein (desmoplakin) levels were unchanged during EPEC infection in vitro.
• In vivo, desmoglein and desmoplakin localization remained unaltered in mice infected with C. rodentium for 7 days.
• Electron microscopy revealed no observable differences in desmosome morphology in infected murine colonocytes compared to controls.

Conclusions:

• Unlike tight junctions, desmosome protein levels, localization, and morphology are not significantly altered during A/E bacterial pathogenesis.
• Desmosomes appear to be resistant to the disruptive effects of A/E pathogens, suggesting a specific targeting of other cellular structures.