The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial Topic

Innate immunity represents the first barrier against bacterial invasion. Toll-like receptors (TLRs) belong to the large family of pattern recognition receptors (PRRs), and their activation leads to the induction of inflammatory cytokines, chemokines, antigen-presenting molecules, and costimulatory m...

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Main Authors: Lorena Elena Meliț, Cristina Oana Mărginean, Cristian Dan Mărginean, Maria Oana Mărginean
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:Journal of Immunology Research
Online Access:http://dx.doi.org/10.1155/2019/8197048
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author Lorena Elena Meliț
Cristina Oana Mărginean
Cristian Dan Mărginean
Maria Oana Mărginean
author_facet Lorena Elena Meliț
Cristina Oana Mărginean
Cristian Dan Mărginean
Maria Oana Mărginean
author_sort Lorena Elena Meliț
collection DOAJ
description Innate immunity represents the first barrier against bacterial invasion. Toll-like receptors (TLRs) belong to the large family of pattern recognition receptors (PRRs), and their activation leads to the induction of inflammatory cytokines, chemokines, antigen-presenting molecules, and costimulatory molecules. Recent studies have focused on identifying the association between TLRs and Helicobacter pylori- (H. pylori-) related diseases. Therefore, this minireview focuses on assessing the role of these TLRs in the development of H. pylori-related gastropathies. Both TLR2 and TLR were found to be involved in H. pylori LPS recognition, with contradictory results most likely due to both the inability to obtain pure LPS in experimental studies and the heterogeneity of the bacterial LPS. In addition, TLR2 was found to be the most extensively expressed gene among all the TLRs in gastric tumors. High levels of TLR4 were also associated with a higher risk of gastric cancer. TLR5 was initially associated with the recognition of H. pylori flagellin, but it seems that this bacterium has developed mechanisms to escape this recognition representing an important factor involved in the persistence of this infection and subsequent carcinogenesis. TLR9, the only TLR with both anti- and proinflammatory roles, was involved in the recognition of H. pylori DNA. The dichotomous role of TLR9, promoting or suppressing the infection, depends on the gastric environment. Recently, TLR7 and TLR8 were shown to recognize purified H. pylori RNA, thereby inducing proinflammatory cytokines. TLR1 and TLR10 gene polymorphisms were associated with a higher risk for gastric cancer in H. pylori-infected individuals. Different gene polymorphisms of these TLRs were found to be associated with gastric cancer depending mostly on ethnicity. Further studies are required in order to develop preventive and therapeutic strategies against H. pylori infections based on the functions of TLRs.
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spelling doaj-art-fed7188afecb463ab93cea183bc178752025-08-20T03:25:39ZengWileyJournal of Immunology Research2314-88612314-71562019-01-01201910.1155/2019/81970488197048The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial TopicLorena Elena Meliț0Cristina Oana Mărginean1Cristian Dan Mărginean2Maria Oana Mărginean3Department of Pediatrics, University of Medicine, Pharmacy, Sciences and Technology Tîrgu Mures, Gheorghe Marinescu Street No. 38, 540136, RomaniaDepartment of Pediatrics, University of Medicine, Pharmacy, Sciences and Technology Tîrgu Mures, Gheorghe Marinescu Street No. 38, 540136, RomaniaUniversity of Medicine, Pharmacy, Sciences and Technology of Tîrgu Mures, Gheorghe Marinescu Street No. 38, 540136, RomaniaDepartment of Pediatrics, University of Medicine, Pharmacy, Sciences and Technology Tîrgu Mures, Gheorghe Marinescu Street No. 38, 540136, RomaniaInnate immunity represents the first barrier against bacterial invasion. Toll-like receptors (TLRs) belong to the large family of pattern recognition receptors (PRRs), and their activation leads to the induction of inflammatory cytokines, chemokines, antigen-presenting molecules, and costimulatory molecules. Recent studies have focused on identifying the association between TLRs and Helicobacter pylori- (H. pylori-) related diseases. Therefore, this minireview focuses on assessing the role of these TLRs in the development of H. pylori-related gastropathies. Both TLR2 and TLR were found to be involved in H. pylori LPS recognition, with contradictory results most likely due to both the inability to obtain pure LPS in experimental studies and the heterogeneity of the bacterial LPS. In addition, TLR2 was found to be the most extensively expressed gene among all the TLRs in gastric tumors. High levels of TLR4 were also associated with a higher risk of gastric cancer. TLR5 was initially associated with the recognition of H. pylori flagellin, but it seems that this bacterium has developed mechanisms to escape this recognition representing an important factor involved in the persistence of this infection and subsequent carcinogenesis. TLR9, the only TLR with both anti- and proinflammatory roles, was involved in the recognition of H. pylori DNA. The dichotomous role of TLR9, promoting or suppressing the infection, depends on the gastric environment. Recently, TLR7 and TLR8 were shown to recognize purified H. pylori RNA, thereby inducing proinflammatory cytokines. TLR1 and TLR10 gene polymorphisms were associated with a higher risk for gastric cancer in H. pylori-infected individuals. Different gene polymorphisms of these TLRs were found to be associated with gastric cancer depending mostly on ethnicity. Further studies are required in order to develop preventive and therapeutic strategies against H. pylori infections based on the functions of TLRs.http://dx.doi.org/10.1155/2019/8197048
spellingShingle Lorena Elena Meliț
Cristina Oana Mărginean
Cristian Dan Mărginean
Maria Oana Mărginean
The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial Topic
Journal of Immunology Research
title The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial Topic
title_full The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial Topic
title_fullStr The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial Topic
title_full_unstemmed The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial Topic
title_short The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial Topic
title_sort relationship between toll like receptors and helicobacter pylori related gastropathies still a controversial topic
url http://dx.doi.org/10.1155/2019/8197048
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