Role of urease in megasome formation and XXXX survival in macrophages.

@entity8777 @entity3265 @entity19 @entity1534 @entity5819 @entity503 @entity2755 @entity7999
Previous studies have demonstrated that @entity1534 (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 @entity19 peritoneal macrophages and @entity19 cells. Plasmid-free mutagenesis was used to replace ureA and ureB with @entity2755 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 @entity7999 , @entity8777 , or @entity503 prevented acidification of phagosomes containing mutant Hp. However, only @entity5819 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 @entity3265 in megasome formation and Hp survival.
