title: In vivo expression of Helicobacter pylori virulence genes in patients with gastritis, ulcer, and gastric cancer.
abstract: The best-studied Helicobacter pylori virulence factor associated with development of peptic ulcer disease or gastric cancer (GC) rather than asymptomatic nonatrophic gastritis (NAG) is the cag pathogenicity island (cagPAI), which encodes a type IV secretion system (T4SS) that injects the CagA oncoprotein into host epithelial cells. Here we used real-time reverse transcription-PCR (RT-PCR) to measure the in vivo expression of genes on the cagPAI and of other virulence genes in patients with NAG, duodenal ulcer (DU), or GC. In vivo expression of H. pylori virulence genes was greater overall in gastric biopsy specimens of patients with GC than in those of patients with NAG or DU. However, since in vitro expression of cagA was not greater in H. pylori strains from patients with GC than in those from patients with NAG or DU, increased expression in GC in vivo is likely a result of environmental conditions in the gastric mucosa, though it may in turn cause more severe pathology. Increased expression of virulence genes in GC may represent a stress response to elevated pH or other environmental conditions in the stomach of patients with GC, which may be less hospitable to H. pylori colonization than the acidic environment in patients with NAG or DU.
authors: Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, UMAE Pediatría, IMSS, México City, Mexico.
authors: Francisco
authors: F
authors: Avilés-Jiménez
authors: Adriana
authors: A
authors: Reyes-Leon
authors: Erik
authors: E
authors: Nieto-Patlán
authors: Lori M
authors: LM
authors: Hansen
authors: Juan
authors: J
authors: Burgueño
authors: Irma P
authors: IP
authors: Ramos
authors: Margarita
authors: M
authors: Camorlinga-Ponce
authors: Hector
authors: H
authors: Bermúdez
authors: Juan M
authors: JM
authors: Blancas
authors: Lourdes
authors: L
authors: Cabrera
authors: Rosa María
authors: RM
authors: Ribas-Aparicio
authors: Jay V
authors: JV
authors: Solnick
authors: Javier
authors: J
authors: Torres-López
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004381:Duodenal Ulcer / Q000382:microbiology*; D005753:Gastric Mucosa / Q000382:microbiology; D005756:Gastritis / Q000382:microbiology*; D015964:Gene Expression Regulation, Bacterial; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000472:pathogenicity*; D006801:Humans; D013274:Stomach Neoplasms / Q000382:microbiology*; D014774:Virulence / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori