Evaluation of the effect of cagPAI genes of Helicobacter pylori on AGS epithelial cell morphology and IL-8 secretion

Abstract

Helicobacter pylori cagPAI genes play an important role in pathogenesis, however little is known about their functions in isolates from Turkish patients. We aimed to evaluate the intactness and the effect of the cagPAI genes (cagT, cagM, cagE, cagA) and cagA EPIYA motifs on the AGS morphological changes and IL-8 induction. Of 53 patients 38 were found infected with H. pylori. PCR amplification of the cagPAI genes showed 42.1 % intact, 39.5 % partially deleted and 18.4 % with complete deletions. Isolates from gastritis, duodenal and gastric ulcer patients with intact and partially deleted cagPAI genes induced higher IL-8 secretion than those with complete deletions. Isolates from gastritis patients had higher deletion frequencies of the cagT and cagM genes than the other two genes. Infection of AGS cells with isolates that possess intact cagPAI and EPIYA-ABC resulted in the formation of the hummingbird phenotype. The cagA positive isolates induced higher IL-8 secretion than cagA negative isolates. Isolates from DU patients with more than one EPIYA-C motif induced higher concentrations of IL-8 than those with EPIYA-ABC. In conclusion, the intactness of the cagPAI in our isolates from different patients was not conserved. An intact cagPAI was found to play an important role in the pathogenesis of DU but not GU or gastritis. The cagA gene, but not other cagPAI genes, was associated with the induction of IL-8 and the morphological changes of the AGS cells. An increase in the number of EPIYA-C motifs had noticeable effect on the formation of the hummingbird phenotype.

Analysis of the intactness of Helicobacter pylori cag pathogenicity island in Iranian strains by a new PCR-based strategy and its relationship with virulence genotypes and EPIYA motifs

“…Accordingly, we targeted a sufficient number of cagPAI genes using eleven sets of primers spanning the island that were potentially involved in the translocation of CagA and also induction of IL-8 from host cells. In previous studies, frequencies of the intactness of the cagPAI were reported to vary between 0% and 100% among H. pylori strains from different geographical regions (Kauser et al, 2004;Kumar et al, 2010;Maeda et al, 1999;Nguyen et al, 2010;Olbermann et al, 2010;Salih et al, 2014). The present study demonstrated that nearly all of our H. pylori strains (96.7%) were cagPAI-positive, including either intact or partial ones.…”

“…Some studies have found a correlation between an intact cagPAI and development of severe clinical outcomes (Jenks et al, 1998;Kidd et al, 2001;Maeda et al, 1999;Nguyen et al, 2010;Nilsson et al, 2003). Recently, Salih et al (2014) reported that isolates from gastritis, duodenal and gastric ulcer patients with intact and even partially deleted cagPAI induced higher IL-8 secretion than those with complete deletions. Similar to these studies, our results showed that strains with intact cagPAI genes were more frequently isolated from patients with PUD (87.5%), GE (83.3%) and GC (80%) than gastritis (61.1%) patients.…”

Human and Helicobacter pylori Interactions Determine the Outcome of Gastric Diseases

“…2.1). Although several bacterial components, such as peptidoglycan (Viala et al 2004) or DNA (Varga et al 2016), can be translocated into host cells through the T4SS and induce an innate immune response, the role of CagA has been evidenced by the following discoveries: i) H. pylori cagA -positive strains induce more CXCL8 than cagA -negative strains (Crabtree et al 1994; Salih et al 2014); ii) cagA mutant strains have reduced ability to stimulate CXCL8 (Brandt et al 2005; Gobert et al 2013); iii) ectopic expression of CagA in gastric epithelial cells stimulates CXCL8 expression (Kim et al 2006); and iv) inhibition of CagA phosphorylation decreases CXCL8 mRNA expression (Gobert et al 2013). Nevertheless, the effect of CagA on CXCL8 induction has not been observed in some studies (Sharma et al 1995), and the various results could be explained by differences in the type of host cells, in the H. pylori strains that have been used, and in the time of infection.…”

Detection of virulence gene belonging to cag pathogenicity island in Helicobacter pylori isolates after multiple unsuccessful eradication therapy in Northwest Croatia

“…Most studies analysed limited number of genes. Salih et al analyzed 4 genes of cagPAI and reported 42.1% of intact, 39.5% of partially deleated and 18.4% completely deleated cagPAI and the correlation of intact cagPAI and duodenal ulcer (17). Baghaei et al analyzed three genes and reported 17% of intact cagPAI, 62% of partially deleated and 20% of completely deleated in Iran population (8).…”