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![Page 1: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/1.jpg)
Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survivalAlain P. Gobert, David J. McGee, Mahmood Akhtar, George L. Mendz, Jamie C. Newton, Yulan Cheng, Harry L. T. Mobley, and Keith T. Wilson
Presented by Mihaela C. Badea-Mic
![Page 2: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/2.jpg)
So, Who Am I?
• Gram negative bacteria
inside the stomach
and duodenum
The Helicobacter Foundation
![Page 3: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/3.jpg)
Who discovered me?
• 1983-Campylobacter pyloridis
• 1997- Tomb et al sequenced the HP genome
• The Helicobacter Foundation,
2005
![Page 4: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/4.jpg)
Epidemiology
• Prevalence (USA)• African-American
• Hispanic
• Eastern Europeans
• UBIQUITOUS
• 50% world population
• The Helicobacter Foundation, 2005
![Page 5: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/5.jpg)
Pathophysiology
• The most common route of H. Pylori infection• Oral to oral• Fecal to oral
PS: watch your pets!
![Page 6: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/6.jpg)
Histology
The Helicobacter Foundation, 2005
![Page 7: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/7.jpg)
Diagnosis
・ Breath test
- Based on the detection of the products of urea
The Helicobacter Foundation, 2005
![Page 8: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/8.jpg)
Diagnosis- cont.
・ Esophagogastroduodenoscopy with biopsy
・ H. Pylori fecal antigen
・ H. Pylori serology
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Diseases
The Helicobacter Foundation, 2005
![Page 10: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/10.jpg)
Diseases- cont.
• Gastric and duodenal ulcers
• Gastric cancer ( 90%)
• Non-ulcer dyspepsia
• Weird syndromes
![Page 11: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/11.jpg)
Treatment
• Antidiarrheals – bistmuth
• Antibiotics - metronidazole, tetracycline, amoxicilin
• Proton pump inhibitors - omeprazole, lansoprazole
• H2 receptor blockers – ranitidine, famotidine
![Page 12: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/12.jpg)
My survival strategies
D. S. Merrel et al, 2004
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My virulence factors
D. M. Monack et al, 2004
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Details
D. M. Monack et al, 2004
![Page 15: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/15.jpg)
And now…finally the paper
• Activated macrophages produce NO using L-arginine as a substrate
• H. Pylori arginase competes with NOS2 for the substrate
• H. Pylori converts the substrate to urea and L-ornithine, not NO
• rocF gene encodes arginase
• Mutations in rocF gene helps the NO to kill H. Pylori
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Experiment # 1A
• Hypothesis - the activated macrophage production of NO is inhibited by wt H. Pylori at physiologic L-arginine concentrations
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Experiment #1A – cont.
Conclusion:
-only the wt H. Pylori inhibited NO released
- the arginase deficient H. Pylori did not inhibit
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Experiment # 1B
• Conclusion:
adding more substrate will stop the competitive inhibition between H. pylori and activated macrophages
![Page 19: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/19.jpg)
Experiment # 2
• Hypothesis – H. Pylori wt compete for the same substrate with activated macrophages. This substrate is L-arginine .
![Page 20: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/20.jpg)
Experiment # 2 –cont.
Conclusion-the wt H. Pylori uses L-arginine decreasing the macrophage NO production because of the loss of the substrate- the rocF mutant does not use the L-arginine
![Page 21: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/21.jpg)
Experiment # 3
• Hypothesis – the macrophage production of NO is regulated by the H. Pylori arginase independently of iNOS expression
• Conclusion- both H. Pylori induce iNOS mRNA expression
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Experiment # 4
• Hypothesis – The bacterial arginase inhibits the release of NO by preformed iNOS in macrophages.
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Experiment # 4-cont
• Conclusion:
the wt H. Pylori inhibits macrophage NO production by the preactivated cells
![Page 24: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/24.jpg)
Experiment # 5
• Hypothesis – Only viable H.pylori can inhibit the release of macrophage NO
• Conclusion : only live H. Pylori can consume the substrate in order to inhibit the iNOS
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Experiment # 6
• Hypothesis – Inhibition of the host cell NO production is a survival strategy for H. Pylori .
• Conclusion – the wt H. Pylori has an increased rate of survival in comparison with rocF mutant H. Pylori in the presence of macrophages .
![Page 26: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/26.jpg)
Experiment # 6 A
![Page 27: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/27.jpg)
Experiment # 6B
Conclusion:The rocF mutant H. Pylori survives in the presence of iNOS -/- macrophages.
![Page 28: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/28.jpg)
Summary
• Bacterial arginase evolutionary adaptation survival strategy for H. pylori gastric mucosa protection
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Don’t let your kids kiss us!
The Helicobacter Foundation, 2005
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Invitation
![Page 31: Helicobacter pylori arginase inhibits nitric oxide production by eukaryotic cells: A strategy for bacterial survival Alain P. Gobert, David J. McGee, Mahmood.](https://reader035.fdocuments.in/reader035/viewer/2022081504/56649eb15503460f94bb777b/html5/thumbnails/31.jpg)
That is all I had to say…
• The End!