title: Impact of cagPAI and T4SS on the inflammatory response of human neutrophils to Helicobacter pylori infection.
abstract: Helicobacter pylori contains a pathogenicity island, cagPAI, with genes homologous to components of the type IV secretion system (T4SS) of Agrobacterium tumefaciens. The T4SS components assemble a structure that transfers CagA protein and peptidoglycan into host epithelial cells, causing the increased release of interleukin 8 (IL8) from the cells. The Toll-like receptors on neutrophils recognize H. pylori, initiating signaling pathways that enhance the activation of NF-κB. However, the roles of cagPAI and T4SS in the inflammatory response of neutrophils are unknown. We evaluated the participation of cagPAI and T4SS in the response of human neutrophils to H. pylori infection. Neutrophils were isolated from the blood of healthy donors and infected with H. pylori cagPAI(+), cagPAI(-), and cagPAI mutant strains virB4 (-) and virD4 (-). Whereas cagPAI(+) strain 26695 induced the greatest IL8 production, a proinflammatory response, cagPAI(-) strain 8822 induced the greatest IL10 production, an anti-inflammatory response. In contrast, the virB4 (-) and virD4 (-) mutant strains produced significantly more of the two proinflammatory cytokines IL1β and tumor necrosis factor αthan the cagPAI(+) strain 26695. We observed that H. pylori downregulated the expression of TLRs 2 and 5 but upregulated TLR9 expression in a cagPAI and T4SS-independent manner. These results show for the first time that the response of human neutrophils to H. pylori may vary from a pro-inflammatory to an anti-inflammatory response, depending on cagPAI and the integrity of T4SS.
authors.affiliation: Unidad de Investigación en Enfermedades Oncológicas, Hospital Infantil de México Federico Gómez, SS Mexico City, México.
authors.forename: Norma Angélica
authors.initials: NA
authors.lastname: Sánchez-Zauco
authors.forename: Javier
authors.initials: J
authors.lastname: Torres
authors.forename: Gloria Erandi
authors.initials: GE
authors.lastname: Pérez-Figueroa
authors.forename: Lourdes
authors.initials: L
authors.lastname: Álvarez-Arellano
authors.forename: Margarita
authors.initials: M
authors.lastname: Camorlinga-Ponce
authors.forename: Alejandro
authors.initials: A
authors.lastname: Gómez
authors.forename: Silvia
authors.initials: S
authors.lastname: Giono-Cerezo
authors.forename: Carmen
authors.initials: C
authors.lastname: Maldonado-Bernal
mesh_terms: D058947:Bacterial Secretion Systems / Q000235:genetics*; D016207:Cytokines / Q000378:metabolism; D015536:Down-Regulation; D044404:Genomic Islands / Q000235:genetics*; D005838:Genotype; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D007249:Inflammation / Q000276:immunology* / Q000382:microbiology*; D009154:Mutation / Q000235:genetics; D009504:Neutrophils / Q000276:immunology*; D051193:Toll-Like Receptors / Q000378:metabolism
chemical_list: D058947:Bacterial Secretion Systems; D016207:Cytokines; D051193:Toll-Like Receptors