Format

Send to

Choose Destination
See comment in PubMed Commons below
World J Gastroenterol. 2011 Jul 28;17(28):3300-9. doi: 10.3748/wjg.v17.i28.3300.

Helicobacter pylori arginase mutant colonizes arginase II knockout mice.

Author information

1
Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.

Abstract

AIM:

To investigate the role of host and bacterial arginases in the colonization of mice by Helicobacter pylori (H. pylori).

METHODS:

H. pylori produces a very powerful urease that hydrolyzes urea to carbon dioxide and ammonium, which neutralizes acid. Urease is absolutely essential to H. pylori pathogenesis; therefore, the urea substrate must be in ample supply for urease to work efficiently. The urea substrate is most likely provided by arginase activity, which hydrolyzes L-arginine to L-ornithine and urea. Previous work has demonstrated that H. pylori arginase is surprisingly not required for colonization of wild-type mice. Hence, another in vivo source of the critical urea substrate must exist. We hypothesized that the urea source was provided by host arginase II, since this enzyme is expressed in the stomach, and H. pylori has previously been shown to induce the expression of murine gastric arginase II. To test this hypothesis, wild-type and arginase (rocF) mutant H. pylori strain SS1 were inoculated into arginase II knockout mice.

RESULTS:

Surprisingly, both the wild-type and rocF mutant bacteria still colonized arginase II knockout mice. Moreover, feeding arginase II knockout mice the host arginase inhibitor S-(2-boronoethyl)-L-cysteine (BEC), while inhibiting > 50% of the host arginase I activity in several tissues, did not block the ability of the rocF mutant H. pylori to colonize. In contrast, BEC poorly inhibited H. pylori arginase activity.

CONCLUSION:

The in vivo source for the essential urea utilized by H. pylori urease is neither bacterial arginase nor host arginase II; instead, either residual host arginase I or agmatinase is probably responsible.

KEYWORDS:

Arginase; Helicobacter pylori; Mice; S-(2-boronoethyl)-L-cysteine; Urease

PMID:
21876618
PMCID:
PMC3160534
DOI:
10.3748/wjg.v17.i28.3300
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Baishideng Publishing Group Inc. Icon for PubMed Central
    Loading ...
    Support Center