Dataset Information

Lactobacillus gasseri Suppresses the Production of Proinflammatory Cytokines in Helicobacter pylori-Infected Macrophages by Inhibiting the Expression of ADAM17.

ABSTRACT: The ability of Helicobacter pylori to evade the host immune system allows the bacterium to colonize the host for a lifetime. Long-term infection with H. pylori causes chronic inflammation, which is the major risk factor for the development of gastric ulcers and gastric cancer. Lactobacilli are part of the human microbiota and have been studied as an adjunct treatment in H. pylori eradication therapy. However, the molecular mechanisms by which lactobacilli act against H. pylori infection have not been fully characterized. In this study, we investigated the anti-inflammatory effects of Lactobacillus strains upon coincubation of host macrophages with H. pylori. We found that Lactobacillus gasseri Kx110A1 (L. gas), a strain isolated from a human stomach, but not other tested Lactobacillus species, blocked the production of the proinflammatory cytokines TNF and IL-6 in H. pylori-infected macrophages. Interestingly, L. gas also inhibited the release of these cytokines in LPS or LTA stimulated macrophages, demonstrating a general anti-inflammatory property. The inhibition of these cytokines did not occur through the polarization of macrophages from the M1 (proinflammatory) to M2 (anti-inflammatory) phenotype or through the altered viability of H. pylori or host cells. Instead, we show that L. gas suppressed the release of TNF and IL-6 by reducing the expression of ADAM17 (also known as TNF-alpha-converting enzyme, TACE) on host cells. Our findings reveal a novel mechanism by which L. gas prevents the production of the proinflammatory cytokines TNF and IL-6 in host macrophages.

SUBMITTER: Gebremariam HG

PROVIDER: S-EPMC6788455 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Lactobacillus gasseri Suppresses the Production of Proinflammatory Cytokines in Helicobacter pylori-Infected Macrophages by Inhibiting the Expression of ADAM17.

Gebremariam Hanna G HG Qazi Khaleda Rahman KR Somiah Tanvi T Pathak Sushil Kumar SK Sjölinder Hong H Sverremark Ekström Eva E Jonsson Ann-Beth AB

Frontiers in immunology 20191004

The ability of Helicobacter pylori to evade the host immune system allows the bacterium to colonize the host for a lifetime. Long-term infection with H. pylori causes chronic inflammation, which is the major risk factor for the development of gastric ulcers and gastric cancer. Lactobacilli are part of the human microbiota and have been studied as an adjunct treatment in H. pylori eradication therapy. However, the molecular mechanisms by which lactobacilli act against H. p ...[more]

PMID: 31636639

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Project description:BACKGROUND AND AIM: Helicobacter pylori eradication clearly decreases peptic ulcer recurrence rates. H. pylori eradication is achieved in 70-90% of cases, but treatment failures due to poor patient compliance and resistant organisms do occur. Lactobacillus gasseri can suppress both clarithromycin-susceptible and -resistant strains of H. pylori in vitro. The aim of this study was to determine the effect of pretreatment with L. gasseri- containing yogurt on H. pylori eradication. We conducted a randomized, controlled clinical trial in patients with H. pylori infection. METHODS: A total of 229 patients were randomized into either a 1-week triple therapy of rabeprazole (10 mg bid), amoxicillin (750 mg bid), and clarithromycin (200 mg bid) or triple therapy plus L. gasseri-containing yogurt. In the yogurt-plus-triple therapy groups, yogurt containing L. gasseri OLL2716 (112 g) was given twice daily for 4 weeks (3 weeks pretreatment and also 1 week during eradication therapy). Clarithromycin resistance was determined by the detection of a mutation in 23S rRNA using nested polymerase chain reaction and the direct sequencing of DNA from pretreatment feces. H. pylori eradication was diagnosed based on the urea breath test and a stool antigen test after 8 weeks of eradication. RESULTS: The status of H. pylori susceptibility to clarithromycin was successively determined in 188 out of 229 samples. The rate of infection with clarithromycin-resistant strains of H. pylori was 27.1%. Overall eradication (intention to treat/per protocol) was 69.3/74.5% for the triple-only group, and 82.6/85.6% for the yogurt-plus-triple group (P = 0.018/P = 0.041). Eradication of primary clarithromycin-resistant strains tended to be higher for yogurt-plus-triple therapy than triple-only therapy (38.5 vs 28.0%, respectively, P = 0.458). CONCLUSION: This study confirmed that the major cause of treatment failure is resistance to clarithromycin. A 4-week treatment with L. gasseri-containing yogurt improves the efficacy of triple therapy in patients with H. pylori infection.

Project description:Helicobacter pylori causes chronic gastritis and avoids elimination by the immune system of the infected host. The commensal bacterium Lactobacillus acidophilus has been suggested to exert beneficial effects as a supplement during H. pylori eradication therapy. In the present study, we applied whole-genome microarray analysis to compare the immune responses induced in murine bone marrow-derived macrophages (BMDMs) stimulated with L. acidophilus, H. pylori, or both bacteria in combination. While L. acidophilus induced a Th1-polarizing response characterized by high expression of interferon beta (IFN-?) and interleukin 12 (IL-12), H. pylori strongly induced the innate cytokines IL-1? and IL-1?. In BMDMs prestimulated with L. acidophilus, H. pylori blocked the expression of L. acidophilus-induced IFN-? and IL-12 and suppressed the expression of key regulators of the Rho, Rac, and Cdc42 GTPases. The inhibition of L. acidophilus-induced IFN-? was independent of H. pylori viability and the virulence factor CagPAI; however, a vacuolating cytotoxin (vacA) mutant was unable to block IFN-?. Confocal microscopy demonstrated that the addition of H. pylori to L. acidophilus-stimulated BMDMs redirects intracellular processing, leading to an accumulation of L. acidophilus in the endosomal and lysosomal compartments. Thus, our findings indicate that H. pylori inhibits the development of a strong Th1-polarizing response in BMDMs stimulated with L. acidophilus by blocking the production of IFN-? in a VacA-dependent manner. We suggest that this abrogation is caused by a redirection of the endocytotic pathway in the processing of L. acidophilus. IMPORTANCE Approximately half of the world's population is infected with Helicobacter pylori. The factors that allow this pathogen to persist in the stomach and cause chronic infections have not yet been fully elucidated. In particular, how H. pylori avoids killing by macrophages, one of the main types of immune cell underlying the epithelium, remains elusive. Here we have shown that the H. pylori virulence factor VacA plays a key role by blocking the activation of innate cytokines induced by the probiotic Lactobacillus acidophilus in macrophages and suppresses the expression of key regulators required for the organization and dynamics of the intracellular cytoskeleton. Our results identify potential targets for the treatment of H. pylori infection and vaccination, since specific inhibition of the toxin VacA possibly allows the activation of an efficient immune response and thereby eradication of H. pylori in the host.

Dataset Information

Lactobacillus gasseri Suppresses the Production of Proinflammatory Cytokines in Helicobacter pylori-Infected Macrophages by Inhibiting the Expression of ADAM17.

Publications

<i>Lactobacillus gasseri</i> Suppresses the Production of Proinflammatory Cytokines in <i>Helicobacter pylori</i>-Infected Macrophages by Inhibiting the Expression of ADAM17.

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