title: Regulation of cathepsin X overexpression in H. pylori-infected gastric epithelial cells and macrophages.
abstract: Cathepsin X (CTSX) is strongly up-regulated in Helicobacter pylori-infected gastric mucosa and intestinal-type gastric cancer. The overexpression of CTSX is mediated predominantly by associated macrophages; depends on a functional type IV-secretion system; and leads to increased migration of gastric epithelial cells. In the present study, we analysed the role of CagA in CTSX overexpression and identified H. pylori-induced inflammatory factors and signalling pathways required for stimulating CTSX expression by H. pylori. Gastric epithelial cells were co-cultured with macrophages in Transwell chambers of 0.4 microm pore size, enabling exchange of fluids but retracting H. pylori. N87 gastric epithelial cells were infected with H. pylori P1 wild-type strain in the presence of inhibitors for p38, JNK, and ERK1/2 signal transduction pathways. Furthermore, cytokines and growth factors were tested for their regulatory function using inhibitory antibodies, and their gene expression was studied by quantitative RT-PCRs and western blots. CTSX is strongly up-regulated at both the mRNA and the protein levels by TNF-alpha, IL-1beta, IL-6, and IL-8, depending on cell type. All these cytokines were found to be increased by five- to ten-fold in macrophages by H. pylori infection of co-cultured N87 gastric epithelial cells. In macrophages, H. pylori up-regulated CTSX via ERK1/2 signalling pathways, and in N87 cells via JNK irrespective of p38 signalling. Our results suggest that H. pylori induced overexpression of CTSX in macrophages and epithelium through specific cytokines that are initiated by CagA-dependent pathways in a cell type-dependent manner.
authors.affiliation: Institute of Pathology, Otto-von-Guericke University, Leipziger Strasse 44, D-39120 Magdeburg, Germany. sabine.krueger@med.ovgu.de
authors.forename: Sabine
authors.initials: S
authors.lastname: Krueger
authors.forename: Doerthe
authors.initials: D
authors.lastname: Kuester
authors.forename: Anja
authors.initials: A
authors.lastname: Bernhardt
authors.forename: Thomas
authors.initials: T
authors.lastname: Wex
authors.forename: Albert
authors.initials: A
authors.lastname: Roessner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000032:analysis / Q000378:metabolism*; D001426:Bacterial Proteins / Q000032:analysis / Q000378:metabolism*; D015153:Blotting, Western / Q000379:methods; D016022:Case-Control Studies; D056657:Cathepsin K; D002403:Cathepsins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D016207:Cytokines / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D005756:Gastritis / Q000378:metabolism*; D005773:Gastroscopy; D016481:Helicobacter Infections / Q000378:metabolism*; D016480:Helicobacter pylori; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D016207:Cytokines; C080866:cagA protein, Helicobacter pylori; D002403:Cathepsins; C534130:CTSK protein, human; D056657:Cathepsin K