Toll-like receptor (TLR2, TLR4 and TLR5) gene polymorphisms and Helicobacter pylori infection in children with and without duodenal ulcer

TLR4 rs4986790 polymorphism confers risk to Helicobacter pylori infection in Zhejiang, China and its enlightenment to nursing care

PURPOSE

Previous literatures on the association between TLR4 gene rs4986790 polymorphism and Helicobacter pylori infection risk reported conflict results. We conducted a case-control study and meta-analysis to investigate whether TLR4 gene rs4986790 polymorphism confers risk to Helicobacter pylori infection.

PATIENTS AND METHODS

254 patients with Helicobacter pylori positive and 235 patients with Helicobacter pylori negative were enrolled. PubMed, Embase, CNKI (Chinese national knowledge internet) were carefully searched and reviewed. Odds ratio (OR) together with 95% confidence interval (CI) were applied to calculate the association power.

RESULTS

GG genotype of TLR4 gene rs4986790 polymorphism contributes increased risk to the population of Zhejiang, China (p = 0.019). Meta-analysis found that the positive findings came from Asian population by allele contrast (p = 0.006), homozygote comparison (p = 0.006) and recessive genetic model (p = 0.001).

CONCLUSION

TLR4 gene rs4986790 polymorphism is associated with Helicobacter pylori infection risk for population of Zhejiang, China. Combined with individual gene polymorphism, the accuracy of risk assessment of Helicobacter pylori infection can be improved and individualized health education can be provided for patients with Helicobacter pylori infection by nurses.

Association of toll-like receptor 4, 5 and 10 polymorphisms with Helicobacter pylori-positive peptic ulcer disease in a center in Jordan

BACKGROUND

Helicobacter pylori infection is widespread, affecting about 50% of the global population. Polymorphisms in host genes such as the toll-like receptor 4 (TLR4) might affect the susceptibility and severity of infection and treatment success.

OBJECTIVE

Investigate the susceptibility and severity of H pylori infection with host TLR4 (rs11536889, rs4986790, rs200109652, rs10759932), TLR5 (rs5744174, rs2072493, rs746250566), TLR10 (rs559182335, rs10004195) polymorphisms.

DESIGN

Analytical, cross-sectional.

SETTING

Endoscopy clinic at tertiary care center.

PATIENTS AND METHODS

Genomic DNA was extracted from formalin-fixed paraffin-embedded tissues collected from H pylori-infected patients and healthy individuals. The single nucleotide polymorphisms (SNPs) within the targeted TLR genes were genotyped to assess the genetic association of various SNPs with disease severity.

MAIN OUTCOME MEASURES

Effect of genotype distribution on H pylori infection.

SAMPLE SIZE

250 peptic ulcer patients and 217 controls.

RESULTS

The TLR10 genotype showed no significant association with H pylori infection except for rs10004195 (T>A) (P=.002). The genotype frequency of Rs5744174 in TLR5 had a significant association with the presence of H pylori infection (P=.046, OR=0.52). Except for gender (P=.022), there were no significant associations between clinical and demographic variables and SNPs relating to the severity of the H pylori infections.

CONCLUSIONS

Our findings are consistent with differences in severity of H pylori infection due to TLR SNPs in different ethnic groups. Understanding differences in genetic susceptibility could help in classifying patients and matching patients with various treatment options on a genetic basis.

LIMITATIONS

Lack of H pylori pathogenicity features assessment.

CONFLICTS OF INTEREST

None.

Association between Toll-like receptor gene polymorphisms and risk of Helicobacter pylori infection: A protocol for systematic review and meta-analysis

BACKGROUND

There were many case-control studies performed the association between TLRs gene polymorphisms and the correlation of Helicobactor pylori infection, these results were inconformity. Therefore, a comprehensive meta-analysis was performed to evaluate the TLRs gene polymorphism and susceptibility to H. pylori infection.

METHODS

Eligible studies were searched from PubMed, EMBASE, Web of science, Cochrane library, CNKI, CBM, Wan Fang Database and VIP Database, all the databases were searched from inception to December 2020. OR with the corresponding 95% CI were presented as associations between certain TLR gene polymorphism and the risk of H. pylori infection, all the included data will be analyzed with the software of Review Manager 5.2 and STATA 14.2.

RESULTS

This study will provide a high-quality evidence to find the TLR gene polymorphisms with H. pylori infection susceptibility.

CONCLUSION

This study will explore which TLR genotype increase the risk of H. pylori infection.

Association of toll-like receptors 2, 4, 9 and 10 genes polymorphisms and Helicobacter pylori-related gastric diseases in Saudi patients

Purpose

Helicobacter pylori is one of the most prevalent human pathogens worldwide. However, the outcomes of H. pylori infection are markedly variable from asymptomatic mild lesion to malignant transformation. Many factors are suggested to influence these infection outcomes, including host immunity and genetic susceptibility. Toll-like receptors (TLRs) can recognise different microbial components and play an essential role in the mucosal immune response against H. pylori infection.

Materials and Methods

The association between the common single nucleotide polymorphisms (SNPs) in the genes of TLR2, 4, 9 and 10 and H. pylori-related gastric diseases were investigated by molecular methods after the confirmation of H. pylori infection. The study included 210 patients in three groups; chronic gastritis (n = 90), peptic ulcer disease (PUD) (n = 75) and gastric carcinoma (n = 45).

Results

The results showed a significant association between TLR4 SNPs (rs 4986790 and rs 4986791) and the presence of H. pylori infection, especially in chronic gastritis patient group. Furthermore, TLR9-rs352140 TT genotype was more prevalent among chronic gastritis patient group. TLR10-rs 10004195 TT genotype was found to be less prevalent among H. pylori-related chronic gastritis and PUD and was suspected to have a protective effect. TLR2 SNPs (rs3804099 and rs3804100) showed no significant statistical difference between H. pylori-infected patients and the controls.

Conclusion

TLR genes polymorphisms may play a role in H. pylori infection susceptibility and may influence its outcomes; however, the ethnic and other factors may modify this effect.

Association of a single nucleotide polymorphism in the TLR2 gene (rs3804099), but not in the TLR4 gene (rs4986790), with Helicobacter pylori infection and peptic ulcer

BACKGROUND/AIMS

Toll-like receptors (TLRs), particularly TLR2 and TLR4, take part in elicitation of immune responses against Helicobacter pylori (H. pylori). This study aimed to investigate the relationship between single nucleotide polymorphisms (SNP) rs3804099 in the TLR2 gene and rs4986790 in the TLR4 gene with H. pylori infection and peptic ulcer (PU).

MATERIALS AND METHODS

Blood specimens were obtained from 350 individuals, including 100 H. pylori-infected patients with PU, 125 H. pylori-infected asymptomatic subjects (AS), and 125 non-infected healthy subjects (NHS). The DNA was extracted, and the SNPs were determined using ARMS-PCR method.

RESULTS

The frequency of CT genotype at TLR2 SNP rs3804099 in both the PU and AS groups was significantly higher than in the NHS group (p<0.05). In total H. pylori-infected individuals (PU+AS), the frequency of the CT genotype at rs3804099 was also significantly higher than in the NHS group (p<0.005). The frequency of the CC genotype at rs3804099 in PU+AS was markedly lower than in the NHS group (p=0.066). PU patients carried CT genotype more frequently than total healthy individuals (AS+NHS) (p<0.03). The distribution of the TT genotype was lower, whereas the frequency of the CT genotype was higher in AS individuals infected with CagA+ strains than those infected with CagA- strains (p<0.03). No significant differences were found among the PU, AS, and NHS groups regarding the genetic differences at rs4986790 in the TLR4 gene.

CONCLUSION

These results provide evidence regarding the association of the rs3804099 in the TLR2 gene with H. pylori infection and PU. The rs3804099 may affect vulnerability to H. pylori infection, particularly to CagA+ strains of bacteria.

Genetic Variability as a Regulator of TLR4 and NOD Signaling in Response to Bacterial Driven DNA Damage Response (DDR) and Inflammation: Focus on the Gastrointestinal (GI) Tract

The fundamental role of human Toll-like receptors (TLRs) and NOD-like receptors (NLRs), the two most studied pathogen recognition receptors (PRRs), is the protection against pathogens and excessive tissue injury. Recent evidence supports the association between TLR/NLR gene mutations and susceptibility to inflammatory, autoimmune, and malignant diseases. PRRs also interfere with several cellular processes, such as cell growth, apoptosis, cell proliferation, differentiation, autophagy, angiogenesis, cell motility and migration, and DNA repair mechanisms. We briefly review the impact of TLR4 and NOD1/NOD2 and their genetic variability in the process of inflammation, tumorigenesis and DNA repair, focusing in the gastrointestinal tract. We also review the available data on new therapeutic strategies utilizing TLR/NLR agonists and antagonists for cancer, allergic diseases, viral infections and vaccine development against both infectious diseases and cancer.

Toll-like receptor 2: An important immunomodulatory molecule during Helicobacter pylori infection

Toll like receptors (TLRs) are an essential subset of pathogen recognition receptors (PRRs) which identify the microbial components and contribute in the regulation of innate and adaptive immune responses against the infectious agents. The TLRs, especially TLR2, TLR4, TLR5 and TLR9, participate in the induction of immune response against H. pylori. TLR2 is expressed on a number of immune and non-immune cells and recognizes a vast broad of microbial components due to its potential to form heterodimers with other TLRs, including TLR1, TLR6 and TLR10. A number of H. pylori-related molecules may contribute to TLR2-dependent responses, including HP-LPS, HP-HSP60 and HP-NAP. TLR2 plays a pivotal role in regulation of immune response to H. pylori through activation of NF-κB and induction of cytokine expression in epithelial cells, monocytes/macrophages, dendritic cells, neutrophils and B cells. The TLR2-related immune response that is induced by H. pylori-derived components may play an important role regarding the outcome of the infection toward bacterial elimination, persistence or pathological reactions. The immunomodulatory and immunoregulatory roles of TLR2 during H. pylori infection were considered in this review. TLR2 could be considered as an interesting therapeutic target for treatment of H. pylori-related diseases.

The Importance of Toll-like Receptors in NF-κB Signaling Pathway Activation by Helicobacter pylori Infection and the Regulators of this Response

Helicobacter pylori (H. pylori) is a common pathogenic bacterium in the stomach that infects almost half of the population worldwide and is closely related to gastric diseases and some extragastric diseases, including iron-deficiency anemia and idiopathic thrombocytopenic purpura. Both the Maastricht IV/Florence consensus report and the Kyoto global consensus report have proposed the eradication of H. pylori to prevent gastric cancer as H.pylori has been shown to be a major cause of gastric carcinogenesis. The interactions between H. pylori and host receptors induce the release of the proinflammatory cytokines by activating proinflammatory signaling pathways such as nuclear factor kappa B (NF-κB), which plays a central role in inflammation, immune response, and carcinogenesis. Among these receptors, Toll-like receptors (TLRs) are classical pattern recognition receptors in the recognition of H. pylori and the mediation of the host inflammatory and immune responses to H. pylori. TLR polymorphisms also contribute to the clinical consequences of H. pylori infection. In this review, we focus on the functions of TLRs in the NF-κB signaling pathway activated by H. pylori, the regulators modulating this response, and the functions of TLR polymorphisms in H.pylori-related diseases.

Polymorphisms in TLR9 but not in TLR5 increase the risk for duodenal ulcer and alter cytokine expression in the gastric mucosa

Colonization of the gastric mucosa by Helicobacter pylori can lead to peptic ulcer and gastric adenocarcinoma. TLRs are signaling receptors involved in the recognition of microorganisms, and polymorphisms in their genes may influence the innate and adaptive immune response to H. pylori, affecting the clinical outcomes of the infection. We assessed the association between single nucleotide polymorphisms in TLR9 and TLR5 and gastroduodenal diseases. All patients were genotyped by allelic discrimination in regions 1174C>T and 1775A>G of TLR5 and -1237T>C and 2848G>A of TLR9. The 2848A allele of TLR9 was more frequent in duodenal ulcer and showed an association of risk with this pathology. Polymorphisms in TLR5 were not found to be associated with disease. Patients with polymorphisms in TLR9 and TLR5 expressed significantly lower levels of IL-1β and TNF-α, whereas polymorphisms in TLR5 also decreased the expression of IL-6 and IL-10. Our findings suggest that 2848G>A polymorphism in TLR9 increases the risk for the development of duodenal ulcer probably by modifying the inflammatory response to H. pylori infection. This is the first study to show an association of 2848A allele of TLR9 with duodenal ulcer and with altered expression of inflammatory cytokines in the gastric mucosa.

Association of genetic variants of membrane receptors related to recognition and induction of immune response with Helicobacter pylori infection in Ecuadorian individuals

Helicobacter pylori (Hp) has a worldwide distribution showing its higher prevalence of infection in developing countries. Toll-like receptors (TLRs) and C-type lectin receptors (CLRs) are proteins that recognize pathogen-associated molecular patterns (PAMPs) and initiate an innate immune response by promoting growth and differentiation of specialized hematopoietic cells for host defense. Gastric infections led by Hp induce a Th-1 cellular immune response, regulated mainly by the expression of IFN-γ. In this retrospective case-control study, we evaluated the TLR1 1805T/G, TLR2 2029C/T, TLR4 896A/G, CD209 -336A/G and IFNGR1 -56C/T polymorphisms and their relationship with susceptibility to Hp infection. TLR1 1805T/G showed statistical differences when the control (Hp-) and infected (Hp+) groups (P = 0.041*) were compared; the TLR1 1805G allele had a protective effect towards infection (OR = 0.1; 95% CI = 0.01-0.88, P = 0.033*). Similarly, the IFNGR1 -56C/T polymorphism showed statistical differences between Hp+ and Hp- (P = 0.018*), and the IFNGR1 -56TT genotype exhibited significant risk to Hp infection (OR = 2.9, 95% CI = 1.27-6.54, P = 0.018*). In conclusion, the pro-inflammatory TLR1 1805T and IFNGR1 -56T alleles are related with susceptibility to Hp infection in Ecuadorian individuals. The presence of these polymorphisms in individuals with chronic infection increases the risk of cellular damage and diminishes the cellular immune response efficiency towards colonizing agents.

The role of TLR4 896 A>G and 1196 C>T in susceptibility to infections: a review and meta-analysis of genetic association studies

Background

Toll-like receptor 4 plays a role in pathogen recognition, and common polymorphisms may alter host susceptibility to infectious diseases.

Purpose

To review the association of two common polymorphisms (TLR4 896A>G and TLR4 1196C>T) with infectious diseases.

Data Sources

We searched PubMed and EMBASE up to March 2013 for pertinent literature in English, and complemented search with references lists of eligible studies.

Study Selection

We included all studies that: reported an infectious outcome; had a case-control design and reported the TLR4 896A>G and/or TLR4 1196C>T genotype frequencies; 59 studies fulfilled these criteria and were analyzed.

Data Extraction

Two authors independently extracted study data.

Data Synthesis

The generalized odds ratio metric (OR_G) was used to quantify the impact of TLR4 variants on disease susceptibility. A meta-analysis was undertaken for outcomes reported in >1 study. Eleven of 37 distinct outcomes were significant. TLR4 896 A>G increased risk for all parasitic infections (OR_G 1.59; 95%CI 1.05-2.42), malaria (1.31; 95%CI 1.04-1.66), brucellosis (2.66; 95%CI 1.66-4.27), cutaneous leishmaniasis (7.22; 95%CI 1.91-27.29), neurocysticercosis (4.39; 95%CI 2.53-7.61), Streptococcus pyogenes tonsillar disease (2.93; 95%CI 1.24-6.93) , typhoid fever (2.51; 95%CI 1.18-5.34) and adult urinary tract infections (1.98; 95%CI 1.04-3.98), but was protective for leprosy (0.36; 95%CI 0.22-0.60). TLR4 1196 C>T effects were similar to TLR4 896 A>G for brucellosis, cutaneous leishmaniasis, leprosy, typhoid fever and S. pyogenes tonsillar disease, and was protective for bacterial vaginosis in pregnancy (0.55; 95%CI 0.31-0.98) and Haemophilus influenzae tonsillar disease (0.42; 95%CI 0.17-1.00). The majority of significant associations were among predominantly Asian populations and significant associations were rare among European populations.

Conclusions

Depending on the type of infection and population, TLR4 polymorphisms are associated with increased, decreased or no difference in infectious disease. This may be due to differential functional expression of TLR4, the co-segregation of TLR4 variants or a favorable inflammatory response.

Characterization of gene polymorphisms related to immune system physiology in Mangalarga horses

The objectives of this study were to standardize a PCR-RFLP genotyping method for the AY_731081:g.1900T>C SNP of the equine CD14 gene, and to characterize this SNP and two other polymorphisms (AY_005808: c.1530A>G of the TLR4 gene and AX_463789: g.133T>C of the Cε gene) in Mangalarga horses, in order to contribute to future studies investigating the association between DNA markers and traits related to immune system physiology in this breed. A total of 151 Mangalarga horses of both sexes and variable ages, representative of the population of São Paulo State, were used. PCR-RFLP was found to be adequate for genotyping of the AY_731081: g.1900T>C SNP of the equine CD14 gene. However, this polymorphism is probably not present in Mangalarga horses, thus impairing association studies using this marker in the breed. The population genetic parameters obtained for the TLR4 AY_005808:c.1530A>G and Cε AX_463789:g.133T>C polymorphisms suggest the use of these markers in association studies with immune system-related traits in Mangalarga horses.

Relationship between toll-like receptor 2 nonsynonymous single nucleotide polymorphisms and the effectiveness of Bacille Calmette-Guérin immunotherapy in preventing recurrence of superficial bladder cancer: A prospective study

BACKGROUND

Intravesical Bacille Calmette-Guérin (BCG) immunotherapy has been used for several decades as a prophylactic approach against recurrence of superficial bladder cancer. However, its effectiveness has been both variable and unpredictable. Typically, cancer BCG-immunotherapy aims to redirect or modulate both innate and adaptive immune responses. The consequences of gene polymorphisms in several key immuno-regulatory molecules on the heterogeneity of the response to BCG-immunotherapy have been investigated.

OBJECTIVE

The aim of this study was to evaluate the association of toll-like receptor (TLR) 2 polymorphisms (arginine to glutamine substitution at position 753 [Arg753Gln] and arginine to tryptophan substitution at position 677 [Arg677Trp]) and the outcome of BCG-immunotherapy.

METHODS

This prospective study was conducted during a 3-year period from June 2006 to July 2009. Consecutive patients were recruited during a 1-year period and followed for 2 years at the Department of Urology, Charles Nicolle Hospital, Tunis, Tunisia. Patients with superficial bladder tumors at stage Ta (noninvasive papillary carcinoma) or T1 (where the tumor has grown from the layer of cells lining the bladder into the connective tissue below but has not grown into the muscle layer of the bladder) of any grade were eligible; carcinoma in situ cases were excluded. The TLR2 Arg753Gln and Arg677Trp polymorphisms were studied in peripheral blood DNA from patients treated with BCG-immunotherapy after transurethral resection.

RESULTS

A total of 112 consecutive patients were enrolled (101 men and 11 women; mean age, 63.9 years [range, 25-85 years]) and completed the 2-year followup. Polymerase chain reaction amplification followed by direct sequencing of the region containing the TLR2 single-nucleotide polymorphism (SNP) of interest did not detect Arg753Gln or Arg677Trp in any of the study participants belonging to either of 2 groups: responders (n = 67) and nonresponders (n = 45) to BCG-immunotherapy.

CONCLUSIONS

No patients included in the study were found to have the 2 known TLR2 nonsynonymous SNPs, and the relative importance of these polymorphisms could not be definitely determined. However, a significant proportion of patients without these polymorphisms responded to BCG-immunotherapy, suggesting that these genetic variants are not critical in the effectiveness of this approach for preventing recurrence of the tumor.

Helicobacter pylori infection in pediatrics

his review summarizes the articles published on Helicobacter pylori infection in children between April 2008 and March 2009. Recent evidence highlights the decreasing prevalence trend of H. pylori infection and supports both intrafamilial and extrafamilial transmission. The association with various symptoms is still being debated. Interestingly, H. pylori infection seems inversely associated with allergic diseases. Monoclonal stool antigen tests are widely used and accurate for the diagnosis of H. pylori infection, but less accurate in young children. The new biprobe real-time PCR assay applied to stools showed a poor sensitivity in children. Using the urea hydrolysis rate next to the delta over baseline values, the (13)C-urea breath test provides excellent results for all age children, even for young children. Treatment of H. pylori infection remains a challenge, considering suboptimal efficacy of current therapy. Among emerging alternatives, sequential treatment appears promising. The adjunction of probiotics to conventional regimens, although eliciting great interest, has shown limited therapeutic benefit.

IL2-330G polymorphic allele is associated with decreased risk of Helicobacter pylori infection in adulthood

We evaluated whether polymorphisms in genes coding molecules linked to the innate and adaptive immune response are associated with susceptibility to Helicobacter pylori infection. IL1B-511C-->T, IL1B-31T-->C, IL1RN allele 2, IL2-330T-->G, TNFA-307G-->A, TLR2Arg677Trp, TLR2Arg753Gln, TLR4Asp299Gly, and TLR5(392STOP) polymorphisms were determined in 541 blood donors. IL2-330T-->G allele carriers had a decreased H. pylori infection risk (OR=0.63, 95% CI=0.43-0.93) after adjustment for demographic and environmental factors. Hence, we investigated whether the polymorphism is functional by evaluating IL-2 serum concentration in 150 blood donors and 100 children. IL-2 pro-inflammatory and anti-inflammatory properties were indirectly investigated by determining serum IFN-gamma and IL-10/TGF-beta levels. The polymorphism was associated with increased mean IL-2 levels in H. pylori-positive adults (2.65 pg/mL vs. 7.78 pg/mL) and children (4.19 pg/mL vs. 8.03 pg/mL). Increased IL-2 was associated with pro-inflammatory activity in adults (IFN-gamma=18.61 pg/mL vs. 25.71 pg/mL), and with anti-inflammatory activity in children (IL-10=6.99 vs. 14.17 pg/mL, TGF-beta=45.88 vs. 93.44 pg/mL) (p<10(-3) for all). In conclusion, in the context of H. pylori infection, IL2-330 T-->G polymorphism is functional and is associated with decreased risk of infection in adults.