Surface layer proteins from Lactobacillus helveticus ATCC® 15009™ affect the gut barrier morphology and function

Area of Science:

• Microbiology
• Gastroenterology
• Immunology

Background:

• Paraprobiotics and postbiotics offer alternatives to probiotics for maintaining intestinal epithelial barrier (IEB) health.
• Lactobacillus helveticus surface layer proteins (S-layer) were explored for their effects on IEB modulation.

Purpose of the Study:

• To investigate the effects of S-layer from Lb ATCC® 15009™ as a paraprobiotic on IEB morpho-functional properties.
• To compare S-layer effects with live or heat-inactivated Lb ATCC® 15009™ in vitro.

Main Methods:

• Co-culture of Caco-2/HT-29 cells to model the intestinal epithelial barrier.
• Measurement of transepithelial electrical resistance (TEER) and paracellular permeability.
• Immunofluorescence (IF) for tight junction proteins (Claudin-1).
• Transmission electron microscopy (TEM) for structural analysis.
• Assessment of alkaline phosphatase activity and interleukin-8 release.

Main Results:

• Live or inactivated Lb ATCC® 15009™ impaired IEB function and Claudin-1 distribution.
• S-layer improved TEER and reduced permeability in basal and LPS-challenged conditions.
• S-layer induced TJ rearrangement and desmosome formation, counteracting LPS effects.
• S-layer did not restore IEB function against pro-inflammatory cytokines (TNF-α + IFN-γ).

Conclusions:

• S-layer from Lb ATCC® 15009™ exhibits a paraprobiotic role, enhancing IEB integrity.
• S-layer demonstrates therapeutic potential for gastrointestinal disorders and related extra-intestinal conditions.