Outer membrane protein expression profile in Helicobacter pylori clinical isolates

Area of Science:

• Microbiology
• Infectious Diseases
• Molecular Biology

Background:

• Helicobacter pylori, a gastric pathogen, possesses numerous outer membrane proteins (OMPs) with poorly understood roles in infection.
• The Hop and Hor protein families comprise 33 members, including known adhesins like AlpA, AlpB, BabA, SabA, and HopZ.

Purpose of the Study:

• To investigate the expression profiles of eight specific outer membrane protein genes (omp) in 200 clinical isolates of H. pylori.
• To correlate OMP expression with host factors and interleukin-8 (IL-8) production.

Main Methods:

• Analysis of omp gene expression (alpA, alpB, babA, babB, babC, sabA, hopM, oipA) in 200 patient-derived H. pylori isolates.
• Detection of OMP production and assessment of BabA/SabA binding capabilities.
• Evaluation of IL-8 expression in gastric cells in relation to the cag pathogenicity island, OipA, and CagA presence.

Main Results:

• AlpA and AlpB were ubiquitously expressed, indicating essential functions.
• Expression of other OMPs varied significantly (35-73%), suggesting adaptation to specific hosts or niches.
• BabA and SabA were produced in a subset of isolates (11% and 5%, respectively) but did not always mediate substrate binding.
• IL-8 production was dependent on the cag pathogenicity island, with OipA enhancing IL-8 levels.
• CagA presence correlated with BabA and OipA expression.

Conclusions:

• H. pylori exhibits remarkably diverse omp expression profiles in clinical isolates.
• This diversity likely reflects adaptive pressures related to adhesion, varying across hosts and over time within a single host.