Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Based on clinical studies, a negative association between Helicobacter pylori and autoimmune corpus gastritis is described. In the present investigation of an unselected population of 1461 adults we can state, however, that there exists a relationship between H. pylori infection and the development of gastric corpus autoimmunity. As confirmation for the gastric autoantibody development through molecular mimicry, a high homology (72% in 25 amino acid overlap) between the beta subunit of H. pylori urease and that of H + K + ATPase, the gastric parietal cell autoantigen, was revealed.
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PMID:Association of Helicobacter pylori and gastric autoimmunity: a population-based study. 759 5

Previous studies have demonstrated that Helicobacter pylori (Hp) delays its entry into macrophages and persists inside megasomes, which are poorly acidified and accumulate early endosome autoantigen 1. Herein, we explored the role of Hp urease in bacterial survival in murine peritoneal macrophages and J774 cells. Plasmid-free mutagenesis was used to replace ureA and ureB with chloramphenicol acetyltransferase in Hp Strains 11637 and 11916. ureAB null Hp lacked detectable urease activity and did not express UreA or UreB as judged by immunoblotting. Deletion of ureAB had no effect on Hp binding to macrophages or the rate or extent of phagocytosis. However, intracellular survival of mutant organisms was impaired significantly. Immunofluorescence microscopy demonstrated that (in contrast to parental organisms) mutant Hp resided in single phagosomes, which were acidic and accumulated the lysosome marker lysosome-associated membrane protein-1 but not early endosome autoantigen 1. A similar phenotype was observed for spontaneous urease mutants derived from Hp Strain 60190. Treatment of macrophages with bafilomycin A1, NH4Cl, or chloroquine prevented acidification of phagosomes containing mutant Hp. However, only ammonium chloride enhanced bacterial viability significantly. Rescue of ureAB null organisms was also achieved by surface adsorption of active urease. Altogether, our data indicate a role for urease and urease-derived ammonia in megasome formation and Hp survival.
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PMID:Role of urease in megasome formation and Helicobacter pylori survival in macrophages. 1654 3