scholarly journals In situ treatment of H. pylori infection in mice stomach with bioengineered probiotic bacteria releasing guided Antimicrobial peptides

2021 ◽  
Author(s):  
Ankan Choudhury ◽  
Patrick Ortiz ◽  
Christopher Michel Kearney
Keyword(s):  
Microbial Community ◽  
Targeted Therapies ◽  
Probiotic Bacteria ◽  
Microbial Ecosystem ◽  
Prophylactic Measure ◽  
Knock Out ◽  
Microbiome Analysis ◽  
Empty Vector ◽  
H Pylori

Objectives: Targeted therapies seek to selectively eliminate a pathogen without disrupting the resident microbial community. This is even more important when a pathogen like H. pylori resides in stomach, a sensitive microbial ecosystem. Using a probiotic like Lactococcus lactis and bioengineering it to release a guided Antimicrobial Peptide (AMP) targeted towards the pathogen offers a pathway to specifically knock-out the deleterious species and not disturbing the stomach microbiome. Results: Three AMPs, Alyteserin, CRAMP and Laterosporulin, were genetically fused to a guiding peptide MM1, which selectively binds to Vacuolating Toxin A (VacA) of H. pylori and cloned into an excretory vector pTKR inside L. lactis. The probiotics were then fed to mice infected with H. pylori, both as a therapeutic and prophylactic measure, and the samples were collected using a novel gavage method and analyzed using qPCR and Illumina sequencing of the extracted stomach samples over a 10-day period. Microbiome analysis with Next-Gen sequencing also revealed a dysbiosis created by H. pylori, determined by creating a Correlation network model with the relative abundances of taxa across the samples, and this dysbiosis was palliated by the bioengineered probiotics which preserved and boosted key microbiome species and reducing the load of deleterious ones. The bioengineered probiotic also significantly improved the OTU diversity compared to antibiotics and L. lactis cloned with empty vector, with gAMP-L. lactis faring the best. Conclusions: Probiotics bioengineered to excrete guided AMPs can be a novel and useful approach for combating pathogens without endangering the natural microbial flora. Given the wealth of AMPs and guiding ligands, both natural and synthetic, this approach can be adapted to develop a diverse array of chimeric guided AMPs and can be cloned into probiotics to create a safe and effective alternative to conventional chemical antibiotics.

scholarly journals In vitro inhibition of H. pylori in a preferential manner using bioengineered L. lactis releasing guided Antimicrobial peptides

2021 ◽  
Author(s):  
Ankan Choudhury ◽  
Patrick Ortiz ◽  
Christopher Michel Kearney
Keyword(s):  
Microbial Community ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Targeted Therapies ◽  
Microbial Ecosystem ◽  
Knock Out ◽  
E Coli ◽  
In Vitro Inhibition ◽  
H Pylori

Objectives: Targeted therapies seek to selectively eliminate a pathogen without disrupting the resident microbial community. This is even more important when a pathogen like H. pylori resides in stomach, a sensitive microbial ecosystem. Using a probiotic like Lactococcus lactis and bioengineering it to release a guided Antimicrobial Peptide (AMP) targeted towards the pathogen offers a pathway to specifically knock-out the deleterious species and not disturbing the stomach microbiome. Results: Three AMPs, Alyteserin, CRAMP and Laterosporulin, were genetically fused to a guiding peptide MM1, which selectively binds to Vacuolating Toxin A (VacA) of H. pylori and cloned into an excretory vector pTKR inside L. lactis. When cultured together in vitro, the L. lactis bioengineered with guided AMPs selectively killed H. pylori when compared to E. coli or Lactobacillus plantarum, as determined by qPCR. Chemically synthesized Alyteserin and MM1-Alyteserin showed similar preferential inhibition of H. pylori when compared against E. coli, with the MIC of MM1-Alyteserin becoming significantly higher for E. coli than Alytserin whereas no such effet was observed against H. pylori. Conclusions: Probiotics bioengineered to excrete guided AMPs can be a novel and useful approach for combating pathogens without endangering the natural microbial flora. Given the wealth of AMPs and guiding ligands, both natural and synthetic, this approach can be adapted to develop a diverse array of chimeric guided AMPs and can be cloned into probiotics to create a safe and effective alternative to conventional chemical antibiotics.

scholarly journals Modification of the Gastric Mucosal Microbiota by a Strain-Specific Helicobacter pylori Oncoprotein and Carcinogenic Histologic Phenotype

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Jennifer M. Noto ◽  
Joseph P. Zackular ◽  
Matthew G. Varga ◽  
Alberto Delgado ◽  
Judith Romero-Gallo ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Community Structure ◽  
Microbial Community ◽  
Iron Deficiency ◽  
Dependent Manner ◽  
Content Type ◽  
Β Diversity ◽  
H Pylori ◽  
Gastric Microbiota

ABSTRACT Helicobacter pylori is the strongest risk factor for gastric adenocarcinoma; however, most infected individuals never develop this malignancy. Strain-specific microbial factors, such as the oncoprotein CagA, as well as environmental conditions, such as iron deficiency, augment cancer risk. Importantly, dysbiosis of the gastric microbiota is also associated with gastric cancer. To investigate the combinatorial effects of these determinants in an in vivo model of gastric cancer, Mongolian gerbils were infected with the carcinogenic cag+ H. pylori strain 7.13 or a 7.13 cagA isogenic mutant, and microbial DNA extracted from gastric tissue was analyzed by 16S rRNA sequencing. Infection with H. pylori significantly increased gastric inflammation and injury, decreased α-diversity, and altered microbial community structure in a cagA-dependent manner. The effect of iron deficiency on gastric microbial communities was also investigated within the context of infection. H. pylori-induced injury was augmented under conditions of iron deficiency, but despite differences in gastric pathology, there were no significant differences in α- or β-diversity, phyla, or operational taxonomic unit (OTU) abundance among infected gerbils maintained on iron-replete or iron-depleted diets. However, when microbial composition was stratified based solely on the severity of histologic injury, significant differences in α- and β-diversity were present among gerbils harboring premalignant or malignant lesions compared to gerbils with gastritis alone. This study demonstrates that H. pylori decreases gastric microbial diversity and community structure in a cagA-dependent manner and that as carcinogenesis progresses, there are corresponding alterations in community structure that parallel the severity of disease. IMPORTANCE Microbial communities are essential for the maintenance of human health, and when these communities are altered, hosts can become susceptible to inflammation and disease. Dysbiosis contributes to gastrointestinal cancers, and specific bacterial species are associated with this phenotype. This study uses a robust and reproducible animal model to demonstrate that H. pylori infection induces gastric dysbiosis in a cagA-dependent manner and further that dysbiosis and altered microbial community structure parallel the severity of H. pylori-induced gastric injury. Ultimately, such models of H. pylori infection and cancer that can effectively evaluate multiple determinants simultaneously may yield effective strategies for manipulating the gastric microbiota to prevent the development of gastric cancer.

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