Related Experiment Videos
Proinflammatory activity of a cecropin-like antibacterial peptide from Helicobacter pylori
J Bylund1, T Christophe, F Boulay
1The Phagocyte Research Laboratory, Department of Medical Microbiology and Immunology, University of Göteborg, Göteborg, Sweden. Johan.Bylund@microbio.gu.se
Abstract:
Helicobacter pylori, the bacterial pathogen associated with gastritis and peptic ulcers, is highly successful in establishing infection in the human gastric mucosa, a process typically associated with massive infiltration of inflammatory cells. Colonization of the mucosa is suggested to be facilitated by H. pylori-produced cecropin-like peptides with antibacterial properties, giving the microbe a competitive advantage over other bacteria. We show that a cecropin-like antibacterial peptide from H. pylori, Hp(2-20), not only has a potent bactericidal effect but also induces proinflammatory activities in human neutrophils, e.g., upregulation of integrins (Mac-1), induction of chemotaxis, and activation of the oxygen radical producing NADPH-oxidase. Furthermore, we show that these effects are mediated through binding of Hp(2-20) to the promiscuous, G-protein-linked lipoxin A(4) receptor-formyl peptide-like receptor 1.
Insights
Helicobacter pylori uses a peptide, Hp(2-20), to kill competing bacteria and trigger inflammation in neutrophils by binding to the formyl peptide-like receptor 1. This mechanism aids its colonization of the stomach lining.
Area of Science:
- Microbiology and Immunology
- Molecular Biology
Background:
- Helicobacter pylori is a bacterial pathogen causing gastritis and peptic ulcers.
- H. pylori colonization involves inflammatory cell infiltration and may be aided by its own antibacterial peptides.
Purpose of the Study:
- To investigate the role of H. pylori-produced cecropin-like peptides in infection.
- To determine the effects of the peptide Hp(2-20) on human neutrophils and its receptor interactions.
Main Methods:
- Assessed the bactericidal activity of Hp(2-20).
- Evaluated Hp(2-20)-induced proinflammatory responses in human neutrophils, including integrin upregulation, chemotaxis, and NADPH-oxidase activation.
- Investigated the receptor mediating these effects, specifically the formyl peptide-like receptor 1 (FPR1).
Main Results:
- Hp(2-20) exhibits potent bactericidal effects.
- Hp(2-20) induces significant proinflammatory activities in human neutrophils.
- These neutrophil responses are mediated by the binding of Hp(2-20) to the FPR1 receptor.
Conclusions:
- H. pylori-derived Hp(2-20) possesses dual functions: bactericidal activity and induction of host inflammatory responses.
- The peptide's interaction with FPR1 is crucial for its pro-inflammatory effects on neutrophils.
- This mechanism likely contributes to H. pylori's successful colonization and persistence in the gastric mucosa.