Functional association between the Helicobacter pylori virulence factors VacA and CagA.
The Helicobacter pylori virulence factors CagA and VacA are implicated in the development of gastroduodenal diseases. Most strains possessing CagA also possess the more virulent vacuolating form of VacA. This study assessed the significance of possession of both virulence factors in terms of their effect on gastric epithelial cells, using a set of minimally passaged, isogenic VacA, CagA and CagE mutants in H. pylori strains 60190 and 84-183. The cagA and cagE mutants were found to significantly increase VacA-induced vacuolation of epithelial cells, and the vacA mutants significantly increased CagA-induced cellular elongations, compared with wild-type strains, indicating that CagA reduces vacuolation and VacA reduces hummingbird formation. Although epithelial cells incubated with the wild-type H. pylori strains may display both vacuolation and hummingbird formation, it was found that (i) hummingbird length was significantly reduced in vacuolated cells compared with those without vacuolation; (ii) the number of vacuoles was significantly reduced in vacuolated cells with hummingbird formation compared with those without hummingbirds; and (iii) cells displaying extensive vacuolation did not subsequently form hummingbirds and vice versa. VacA did not affect the phosphorylation of CagA. These data show that VacA and CagA downregulate each other's effects on epithelial cells, potentially allowing H. pylori interaction with cells whilst avoiding excessive cellular damage.
Argent
Richard H
RH
Wolfson Digestive Diseases Centre, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.|Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
Thomas
Rachael J
RJ
Wolfson Digestive Diseases Centre, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.|Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
Letley
Darren P
DP
Wolfson Digestive Diseases Centre, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.|Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
Rittig
Michael G
MG
Centre for Biochemistry and Cell Biology, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.
Hardie
Kim R
KR
Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
Atherton
John C
JC
Wolfson Digestive Diseases Centre, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.|Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
D000942:Antigens, Bacterial / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D048430:Cell Shape; D002470:Cell Survival; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*; D017353:Gene Deletion; D016480:Helicobacter pylori / Q000235:genetics / Q000472:pathogenicity*; D016209:Interleukin-8 / Q000378:metabolism; D009499:Neutral Red / Q000378:metabolism; D014617:Vacuoles / Q000382:microbiology; D037521:Virulence Factors / Q000502:physiology*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D016209:Interleukin-8; C103937:PicB protein, Helicobacter pylori; C074689:VacA protein, Helicobacter pylori; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori; D009499:Neutral Red