Mouse Models Of Helicobacter Infection And Gastric Pathologies

An intranasal influenza virus vector vaccine protects against Helicobacter pylori in mice

Helicobacter pylori is a human pathogen that infects almost half of the population. Antibiotic resistance in H. pylori threatens health and increases the demand for prophylactic and therapeutic vaccines. Traditional oral vaccine research faces considerable challenges because of the epithelial barrier, potential enterotoxicity of adjuvants, and the challenging conditions of the gastric environment. We developed an intranasal influenza A virus (IAV) vector vaccine based on two live attenuated influenza viruses with modified acidic polymerase protein (PA) genes encoding the A subunit of H. pylori neutrophil-activating protein (NapA), named IAV-NapA, including influenza virus A/WSN/33 (WSN)-NapA and A/Puerto Rico/8/34 (PR8)-NapA. These recombinant influenza viruses were highly attenuated and exhibited strong immunogenicity in mice. Vaccination with IAV-NapA induced antigen-specific humoral and mucosal immune responses while stimulating robust Th1 and Th17 cell immune responses in mice. Our findings suggest that prophylactic and therapeutic vaccination with influenza virus vector vaccines significantly reduces colonization of H. pylori and inflammation in the stomach of mice.IMPORTANCEHelicobacter pylori is the most common cause of chronic gastritis and leads to severe gastroduodenal pathology in some patients. Many studies have shown that Th1 and Th17 cellular and gastric mucosal immune responses are critical in reducing H. pylori load. IAV vector vaccines can stimulate these immune responses while overcoming potential adjuvant toxicity and antigen dosing issues. To date, no studies have demonstrated the role of live attenuated IAV vector vaccines in preventing and treating H. pylori infection. Our work indicates that vaccination with IAV-NapA induces antigen-specific humoral, cellular, and mucosal immunity, producing a protective and therapeutic effect against H. pylori infection in BALB/c mice. This undescribed H. pylori vaccination approach may provide valuable information for developing vaccines against H. pylori infection.

Curcumin Oxidation Is Required for Inhibition of Helicobacter pylori Growth, Translocation and Phosphorylation of Cag A

Curcumin is a potential natural remedy for preventing Helicobacter pylori-associated gastric inflammation and cancer. Here, we analyzed the effect of a phospholipid formulation of curcumin on H. pylori growth, translocation and phosphorylation of the virulence factor CagA and host protein kinase Src in vitro and in an in vivo mouse model of H. pylori infection. Growth of H. pylori was inhibited dose-dependently by curcumin in vitro. H. pylori was unable to metabolically reduce curcumin, whereas two enterobacteria, E. coli and Citrobacter rodentium, which efficiently reduced curcumin to the tetra- and hexahydro metabolites, evaded growth inhibition. Oxidative metabolism of curcumin was required for the growth inhibition of H. pylori and the translocation and phosphorylation of CagA and cSrc, since acetal- and diacetal-curcumin that do not undergo oxidative transformation were ineffective. Curcumin attenuated mRNA expression of the H. pylori virulence genes cagE and cagF in a dose-dependent manner and inhibited translocation and phosphorylation of CagA in gastric epithelial cells. H. pylori strains isolated from dietary curcumin-treated mice showed attenuated ability to induce cSrc phosphorylation and the mRNA expression of the gene encoding for IL-8, suggesting long-lasting effects of curcumin on the virulence of H. pylori. Our work provides mechanistic evidence that encourages testing of curcumin as a dietary approach to inhibit the virulence of CagA.