Bruno Silva1, Alexandra Nunes2, Filipa F Vale3, Raquel Rocha1, João Paulo Gomes2, Ricardo Dias4, Mónica Oleastro1. 1. National Reference Laboratory for Gastrointestinal Infections, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal. 2. Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal. 3. Host-Pathogen Interactions Unit, Research Institute for Medicines (iMed-ULisboa), Instituto de Medicina Molecular, Faculdade de Farmácia da Universidade de Lisboa, Lisbon, Portugal. 4. Biosystems and Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
Abstract
BACKGROUND: Helicobacter pylori virulence is associated with different clinical outcomes. The existence of an intact dupA gene from tfs4b cluster has been suggested as a predictor for duodenal ulcer development. However, the role of tfs plasticity zone clusters in the development of ulcers remains unclear. We studied several H. pylori strains to characterize the gene arrangement of tfs3 and tfs4 clusters and their impact in the inflammatory response by infected gastric cells. METHODS: The genome of 14 H. pylori strains isolated from Western patients, pediatric (n=10) and adult (n=4), was fully sequenced using the Illumina platform MiSeq, in addition to eight pediatric strains previously sequenced. These strains were used to infect human gastric cells, and the secreted interleukin-8 (IL-8) was quantified by ELISA. The expression of virB2, dupA, virB8, virB10, and virB6 was assessed by quantitative PCR in adherent and nonadherent fractions of H. pylori during in vitro co-infection, at different pH values. RESULTS: We have found that cagA-positive H. pylori strains harboring a complete tfs plasticity zone cluster significantly induce increased production of IL-8 from gastric cells. We have also found that the region spanning from virB2 to virB10 genes constitutes an operon, whose expression is increased in the adherent fraction of bacteria during infection, as well as in both adherent and nonadherent fractions at acidic conditions. CONCLUSIONS: A complete tfs plasticity zone cluster is a virulence factor that may be important for the colonization of H. pylori and to the development of severe outcomes of the infection with cagA-positive strains.
BACKGROUND:Helicobacter pylori virulence is associated with different clinical outcomes. The existence of an intact dupA gene from tfs4b cluster has been suggested as a predictor for duodenal ulcer development. However, the role of tfs plasticity zone clusters in the development of ulcers remains unclear. We studied several H. pylori strains to characterize the gene arrangement of tfs3 and tfs4 clusters and their impact in the inflammatory response by infected gastric cells. METHODS: The genome of 14 H. pylori strains isolated from Western patients, pediatric (n=10) and adult (n=4), was fully sequenced using the Illumina platform MiSeq, in addition to eight pediatric strains previously sequenced. These strains were used to infect human gastric cells, and the secreted interleukin-8 (IL-8) was quantified by ELISA. The expression of virB2, dupA, virB8, virB10, and virB6 was assessed by quantitative PCR in adherent and nonadherent fractions of H. pylori during in vitro co-infection, at different pH values. RESULTS: We have found that cagA-positive H. pylori strains harboring a complete tfs plasticity zone cluster significantly induce increased production of IL-8 from gastric cells. We have also found that the region spanning from virB2 to virB10 genes constitutes an operon, whose expression is increased in the adherent fraction of bacteria during infection, as well as in both adherent and nonadherent fractions at acidic conditions. CONCLUSIONS: A complete tfs plasticity zone cluster is a virulence factor that may be important for the colonization of H. pylori and to the development of severe outcomes of the infection with cagA-positive strains.
Authors: Igor Brasil-Costa; Cintya de Oliveira Souza; Leni Célia Reis Monteiro; Maria Elisabete Silva Santos; Edivaldo Herculano Correa De Oliveira; Rommel Mario Rodriguez Burbano Journal: Pathogens Date: 2022-03-29