title: A potential association between Helicobacter pylori CagA EPIYA and multimerization motifs with cytokeratin 18 cleavage rate during early apoptosis.
abstract: OBJECTIVE
  Helicobacter pylori is a highly diverse pathogen, which encounters epithelial cells as the initial defense barrier during its lifelong infection. The structure of epithelial cells can be disrupted through cleavage of microfilaments. Cytokeratin 18 (CK18) is an intermediate filament, the cleavage of which is considered an early event during apoptosis following activation of effector caspases.
  
  
  METHODS
  Helicobacter pylori strains were isolated from 76 dyspeptic patients. cagA 3' variable region and CagA protein status were analyzed by PCR and western blotting, respectively. Eight hours post-co-culture of AGS cells with different H. pylori strains, flow cytometric analysis was performed using M30 monoclonal antibody specific to CK18 cleavage-induced neo-epitope.
  
  
  RESULTS
  Higher rates of CK18 cleavage were detected during co-culture of AGS cells with H. pylori strains bearing greater numbers of cagA EPIYA-C and multimerization (CM) motifs. On the other hand, H. pylori strains with greater numbers of EPIYA-B relative to EPIYA-C demonstrated a decrease in CK18 cleavage rate. Thus, H. pylori-mediated cleavage of CK18 appeared proportional to the number of CagA EPIYA-C and CM motifs, which seemed to be downplayed in the presence of EPIYA-B motifs.
  
  
  CONCLUSIONS
  Our observation associating the heterogeneity of cagA variants with the potential of H. pylori strains in the induction of CK18 cleavage as an early indication of apoptosis in gastric epithelial cells supports the fact that apoptosis may be a type-specific trait. However, additional cagA-targeted experiments are required to clearly identify the role of EPIYA and CM motifs in apoptosis and/or the responsible effector molecules.
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Samaneh
authors.initials: S
authors.lastname: Saberi
authors.forename: Masoumeh
authors.initials: M
authors.lastname: Douraghi
authors.forename: Kayhan
authors.initials: K
authors.lastname: Azadmanesh
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Shokrgozar
authors.forename: Hojjat
authors.initials: H
authors.lastname: Zeraati
authors.forename: Mahmoud Eshagh
authors.initials: ME
authors.lastname: Hosseini
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Mohagheghi
authors.forename: Mahbubeh
authors.initials: M
authors.lastname: Parsaeian
authors.forename: Marjan
authors.initials: M
authors.lastname: Mohammadi
mesh_terms: D020816:Amino Acid Motifs; D000942:Antigens, Bacterial / Q000235:genetics*; D017209:Apoptosis; D001426:Bacterial Proteins / Q000235:genetics*; D015153:Blotting, Western; D002478:Cells, Cultured; D018920:Coculture Techniques; D004847:Epithelial Cells / Q000382:microbiology*; D005434:Flow Cytometry; D016480:Helicobacter pylori / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D053538:Keratin-18 / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D053538:Keratin-18; C080866:cagA protein, Helicobacter pylori