Mucus is a viscous gel produced by epithelial cells that protects the mucosa of the gastrointestinal tract from potentially harmful microbes ingested with food. Helicobacter pylori is a gram-negative bacterium with a unique preference for the human stomach, where it is the only known colonizer. Infection with H. pylori is associated with various gastrointestinal diseases, including gastric cancer.
The Boccellato group has previously developed a stem cell-driven model of the healthy human stomach known as mucosoid cultures. In this study, the researchers used this technology to induce cells within the mucosoid culture to produce mucus on the apical side. The group then studied the impact of the mucus in controlling microbial invasion, finding that inflammation induces the stomach epithelium to secrete antimicrobial peptides in the mucus. Antimicrobial peptides are naturally occurring antibiotics produced by our own cells. The mucus from inflamed cells exhibits significant anti-H. pylori activity in vitro.
However, it was also noted that the presence of H. pylori infection leads to a decrease in the expression of antimicrobial peptides, indicating that the bacteria have developed mechanisms to circumvent these innate epithelial defenses. This allows H. pylori to persist for decades, increasing the risk of developing gastric cancer.