HpaA Is Essential forHelicobacter pyloriColonization in Mice

Abstract

Infection with the human gastric pathogen Helicobacter pylori can give rise to chronic gastritis, peptic ulcer, and gastric cancer. All H. pylori strains express the surface-localized protein HpaA, a promising candidate for a vaccine against H. pylori infection. To study the physiological importance of HpaA, a mutation of the hpaA gene was introduced into a mouse-adapted H. pylori strain. To justify that the interruption of the hpaA gene did not cause any polar effects of downstream genes or was associated with a second site mutation, the protein expression patterns of the mutant and wild-type strains were characterized by two different proteomic approaches. Two-dimensional differential in-gel electrophoresis analysis of whole-cell extracts and subcellular fractionation combined with nano-liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry for outer membrane protein profiling revealed only minor differences in the protein profile between the mutant and the wild-type strains. Therefore, the mutant strain was tested for its colonizing ability in a well-established mouse model. While inoculation with the wild-type strain resulted in heavily H. pyloriinfected mice, the HpaA mutant strain was not able to establish colonization. Thus, by combining proteomic analysis and in vivo studies, we conclude that HpaA is essential for the colonization of H. pylori in mice.

Helicobacter pylori HP1512 Is a Nickel-Responsive NikR-Regulated Outer Membrane Protein

“…While conducting a survey of nickel-responsive genes, HP1512 (frpB4) was identified as a gene of interest. The presence of HP1512 in membrane preparations has been documented in studies specifically targeting H. pylori OMPs (3,6,14). Previous work characterizing the iron transport and storage genes of H. pylori 26695 demonstrated that while two of the frpB alleles, frpB1 (HP0876) and frpB2/3 (HP0915/0916), were iron responsive, frpB4 (HP1512) was not responsive to either the iron concentration or fur mutation (14,44).…”

Failure To Detect Helicobacter pylori DNA in Drinking and Environmental Water in Dhaka, Bangladesh, Using Highly Sensitive Real-Time PCR Assays

“…In addition, no other bacterial species were detected, with the exception of the closely related H. acinonychis (13), which was detected by the glmM assay. Furthermore, both the glmM and the hpaA genes have been used in similar previous studies (21,22,46), previous phenotypic analyses of Ͼ300 clinical H. pylori isolates have shown that HpaA was expressed in all strains studied (A.-M. Svennerholm, unpublished results), and HpaA has also been shown to be required for colonization of mice (8). The two genes in combination should thus provide a reliable method for quantification of H. pylori genomes in any type of sample.…”

Identification of Helicobacter pylori Genes That Contribute to Stomach Colonization

“…Examples of genes previously shown to be compromised for colonization in the mouse model, when mutated and identified as colonization defective in our screen, include the urease genes (16,22,62), the nickel transporter nikA gene, the fur gene (10), the bacterial ferritin pfr gene (64), the ␤-1-4 galactosyl transferase gene (18), several chemotaxis genes (21,59), and the flagellar sheath-localized adhesin hpaA gene (11). A hallmark of H. pylori infection is infiltration of neutrophils that produce reactive oxygen and nitrogen species, exposing both the host and the bacteria to DNA and protein damage.…”