title: Downregulation of CXCR1 and CXCR2 expression on human neutrophils by Helicobacter pylori: a new pathomechanism in H. pylori infection?
abstract: In Helicobacter pylori gastritis, neutrophil activation and migration, which play central roles in the pathogenesis of the disease, are regulated by the neutrophil attractant chemokines interleukin 8 (IL-8) and Groalpha, whose secretion is induced by H. pylori. However, the modulation of the corresponding chemokine receptors CXCR1 and CXCR2 on human neutrophils under the influence of H. pylori has not been investigated. Incubation of neutrophils with cag(+) and cag deletion H. pylori strains resulted in a complete downregulation of the CXCR1 and the CXCR2 receptors after 0.5 h, as tested by fluorescence-activated cell sorter analysis, independent of the cag status. Downregulation of CXCR1 and CXCR2 seems to occur via receptor internalization and rapid degradation, as shown by confocal microscopy and immunoblotting. Neither the proinflammatory cytokines IL-8 and tumor necrosis factor alpha produced by the neutrophils themselves nor H. pylori lipopolysaccharide, which are the known regulators of these two chemokine receptors, was responsible for the downregulation. Reverse transcription-PCR analysis showed that CXCR1 and CXCR2 mRNAs of neutrophils were reduced at a later time than the CXCR1 and CXCR2 proteins. Moreover, cag(+) H. pylori strains induced significantly stronger downregulation of CXCR1 and CXCR2 mRNAs than the cag deletion mutant. Therefore, receptor protein and mRNA downregulation seem to be mediated by two independent mechanisms. Data obtained by immunohistochemistry suggested that downmodulation of CXCR1 and CXCR2 on neutrophils may also occur in vivo in the human stomach during H. pylori infection. Downregulation of CXCR1 and CXCR2 expression on neutrophils in H. pylori infection by H. pylori itself may represent a new mechanism of modulating neutrophil migration and activation in the gastric mucosa.
authors.affiliation: Institut für Pathologie, Universität Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany. schmausser@web.de
authors.forename: Bernd
authors.initials: B
authors.lastname: Schmausser
authors.forename: Christine
authors.initials: C
authors.lastname: Josenhans
authors.forename: Simon
authors.initials: S
authors.lastname: Endrich
authors.forename: Sebastian
authors.initials: S
authors.lastname: Suerbaum
authors.forename: Cassian
authors.initials: C
authors.lastname: Sitaru
authors.forename: Mindaugas
authors.initials: M
authors.lastname: Andrulis
authors.forename: Stephanie
authors.initials: S
authors.lastname: Brändlein
authors.forename: Peter
authors.initials: P
authors.lastname: Rieckmann
authors.forename: Hans Konrad
authors.initials: HK
authors.lastname: Müller-Hermelink
authors.forename: Matthias
authors.initials: M
authors.lastname: Eck
mesh_terms: D015536:Down-Regulation; D016481:Helicobacter Infections / Q000276:immunology*; D016480:Helicobacter pylori / Q000472:pathogenicity*; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000633:toxicity; D009504:Neutrophils / Q000737:chemistry* / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D023062:Receptors, Interleukin-8A / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D023063:Receptors, Interleukin-8B / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D016209:Interleukin-8; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D023062:Receptors, Interleukin-8A; D023063:Receptors, Interleukin-8B; D014409:Tumor Necrosis Factor-alpha