Quantum changes in Helicobacter pylori gene expression accompany host-adaptation

Area of Science:

• Microbiology
• Genomics
• Pathogen Adaptation

Background:

• Helicobacter pylori is a successful gastric pathogen with high genomic plasticity.
• Understanding H. pylori adaptation mechanisms is crucial for controlling infections.

Purpose of the Study:

• To identify genetic elements enabling H. pylori adaptation to new host environments.
• To compare the genomes of a clinical isolate and its mouse-adapted derivatives.

Main Methods:

• Whole-genome sequencing using PacBio RS and Illumina MiSeq.
• Comparative genomic analysis of H. pylori strains.
• Analysis of gene expression and protein abundance.

Main Results:

• Mice-adapted strains acquired a jhp0562-like allele, encoding a β-1,4-galactosyltransferase essential for Ley antigen expression.
• Intragenomic recombination between babA and babB genes was observed.
• Down-regulation of genes, including outer membrane proteins BabA, BabB, and HopD, was demonstrated, correlating with reduced BabA protein abundance.

Conclusions:

• Acquisition of a galactosyltransferase for Ley antigen expression and reduced outer membrane protein expression may facilitate H. pylori colonization of the mouse gastric epithelium.
• Genomic plasticity, including gene acquisition and altered expression, is key to H. pylori host adaptation.