Genomic features of the Helicobacter pylori strain PMSS1 and its virulence attributes as deduced from its in vivo colonisation patterns

Abstract

The human gastric pathogen Helicobacter pylori occurs in two basic variants, either exhibiting a functional cagPAI-encoded type-4-secretion-system (T4SS) or not. Only a few cagPAI-positive strains have been successfully adapted for long-term infection of mice, including the pre-mouse Sydney strain 1 (PMSS1). Here we confirm that PMSS1 induces gastric inflammation and neutrophil infiltration in mice, progressing to intestinal metaplasia. Complete genome analysis of PMSS1 revealed 1,423 coding sequences, encompassing the cagPAI gene cluster and, unusually, the location of the cytotoxin-associated gene A (cagA) approximately 15 kb downstream of the island. PMSS1 harbours three genetically exchangeable loci that are occupied by the hopQ coding sequences. HopQ represents a critical co-factor required for the translocation of CagA into the host cell and activation of NF-κB via the T4SS. Long-term colonisation of mice led to an impairment of cagPAI functionality. One of the bacterial clones re-isolated at four months post-infection revealed a mutation in the cagPAI gene cagW, resulting in a frame shift mutation, which prevented CagA translocation, possibly due to an impairment of T4SS function. Rescue of the mutant cagW re-established CagA translocation. Our data reveal intriguing insights into the adaptive abilities of PMSS1, suggesting functional modulation of the H. pylori cagPAI virulence attribute.

Helicobacter pylori-Induced Heparanase Promotes H. pylori Colonization and Gastritis

“…H. pylori PMSS1 [cagA + wild type H. pylori prone to colonization in mouse ( 21 )] was kindly provided by Dr. Peng Xie, Department of Gastroenterology, the First Affiliated Hospital of Nanchang University. H. pylori strains were grown in agar plate contained campylobacter agar base (Oxiod, #CM0689, Thermo Fisher Scientific, MA, USA) supplemented with 10% sterile defibrinated sheep blood at 37°C under microaerophilic conditions in 5% oxygen, 10% CO 2 and 85% nitrogen.…”

Repurposing Dihydropyridines for Treatment of Helicobacter pylori Infection

“…The strains were grown in Blood Agar Base No.2 (OXOID) supplemented with 8% defibrinated horse blood (OXOID) in a humidified microaerobic incubator (85% N 2 , 10% CO 2 , 5% O 2 ) at 37 • C for 48-72 h. For certain experiments, bacteria were grown for 48-72 h at 37 • C in brain heart infusion broth (OXOID) supplemented with 4% fetal bovine serum (Gibco). For in vivo experiments, the CagA + mouse colonizing strain pre-mouse Sydney Strain 1 (PMSS1) [20,21], obtained from the French National Reference Center for Campylobacters & Helicobacters (www.cnrch.fr), was used. For infection inocula, H. pylori PMSS1 was grown on in-house selective Wilkins Chalgren agar plates [22] under microaerobic conditions and transferred to Brucella broth medium as described below.…”

“…Animals were housed in polycarbonate cages and acclimatized for one week before starting the experiments. Two groups of 9 mice were fasted to facilitate bacterial colonization and then force-fed for 3 consecutive days with a dose of 10 8 CFU in 100 µL of H. pylori strain PMSS1 [21,28]. Bacterial inocula were freshly prepared in Brucella broth medium from cultures grown on in-house Wilkins Chalgren agar plates supplemented with 10% human blood and 10 µg/mL of vancomycin, 5 µg/mL of trimethoprim, 1 µg/mL of amphotericin B and 2 µg/mL of cefsulodin [22] under microaerobic conditions (85% N 2 , 10% CO 2 , 5% O 2 ) at 35 • C for 48 h.…”

NF-kB-dependent activation of STAT3 by H. pylori is suppressed by TFF1

“…For the mouse infection, we utilized the pre-mouse Sydney strain 1 (PMSS1). PMSS1 is the wild-type rodent-adapted c ag + H. pylori strain derived from the parental strain of the mouse Sydney strain (SS1), acquired form a clinical isolate of a duodenal ulcer patient [ 31 ]. All the H. pylori strains were a gift from Dr.…”