Toll-like Receptor 4 Thr399Ile Polymorphisms Research Articles

ROLE OF TLR2, TLR4 GENE POLYMORPHISM IN DEVELOPING MICROVASCULAR COMPLICATIONS IN ADOLESCENTS WITH TYPE 1 DIABETES MELLITUS

Long-term complications of type 1 diabetes mellitus (T1DM) in children and adolescents are an important problem in modern medicine. Recently, the role of immune mechanisms, in particular, chronic inflammation, in the development of both T1DM and its microvascular complications has been actively discussed. Activation of Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) leads to hyperproduction of proinflammatory cytokines, chemokines, adhesion molecules involved in the formation of diabetic microvascular complications. At the same time, TLR2 and TLR4 gene polymorphism alters the immune susceptibility to the endogenous ligands, which may increase the risk of diabetic microangiopathies. The aim of this study is to evaluate the frequency of genotypes and alleles of TLR2 and TLR4 genes distribution and to determine the content of TNFα, IL-1, VCAM-1, fractalkine, endothelin-1 in adolescents with T1DM with microvascular complications. We examined 139 adolescents with T1DM from 14 to 18 years old and 56 healthy teenagers. Patients with T1DM were divided into two groups: Group I – patients with poor glycemic control (HbA1C > 9.0%), (n = 64); Group II – patients with satisfactory glycemic control of T1DM (HbA1C ≤ 9.0%), (n = 75), including adolescents with optimal (HbA1C < 7.5%) and suboptimal glycemic control (7.5% ≤ HbA1C ≤ 9.0%) (ISPAD clinical practice consensus guidelines 2014). According to the presence of microvascular complications, the groups were subdivided into subgroups: Iа (n = 49), IIа (n = 38) – adolescents with verified microvascular disorders: diabetic retinopathy, nephropathy and neuropathy; Ib (n = 15), IIb (n = 37) – without microvascular complications. Allelic variants of TLR genes were determined using test systems GosNII genetics (Moscow). The content of cytokines in blood serum was carried out by the method of enzyme-linked immunosorbent assay “BIOSCIENCE”. Data were analyzed using software packages Statistica version 6.0. The assessment of TLR2 (Arg753Gln) and TLR4 (Thr399Ile) polymorphism distribution did not reveal significant differences between the observed subgroups and the control. In Ia and IIa subgroups (with complications) Asp299Gly variant was noted to be significantly less common when compared to subgroups Ib, IIb and controls. The presence of Gly allele in TLR4 gene was found to disrupt the expression of TNFα and VCAM-1 and can be considered protective for the development of microvascular complications.

Toll-like Receptor 4 Gene Polymorphisms in Chinese Population After Allogeneic Hematopoietic Stem Cell Transplantation

Objectives:: Graft-versus-host disease (GVHD) is the most common complication after hematopoietic stem cell transplantation (HSCT) and remains to be a major cause of mortality. Activation of toll-like receptor 4 (TLR-4) by lipopolysaccharide induces the NF-κB signaling pathway to release critical proinflammatory cytokines and increases the recipient response to GVHD. In order to clarify the role of TLR-4 in the occurrence of acute GVHD after HSCT, we collected 208 samples from HSCT recipients and their human lecucyte antigen identical donors to test the hypothesis that TLR-4polymorphism in the recipients or donors influence the risk of acute GVHD in allogeneic HSCT recipients. Methods:: TLR-4 Asp299Gly and Thr399Ile polymorphisms of each sample were examined by using DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism methods. Results:: No homozygous or heterozygous variant alleles of the Asp299Gly or Thr339Ile polymorphism were detected in any samples in our study. Our results demonstrate that TLR-4 Asp299Gly and Thr399Ile polymorphisms might be very rare in the Chinese population (Eastern China and Taiwan region). Conclusion:: The results of this study cannot confirm the role of TLR-4 mutations in the pathogenesis of GVHD in humans, yet we reach a definite conclusion by a TLR-4 knockout murine GVHD model in our ongoing project.

THE ROLE OF ADIPONECTIN AND TOLL-LIKE RECEPTOR 4 GENE POLYMORPHISMS ON NON-PROLIFERATIVE RETINOPATHY IN TYPE 2 DIABETES MELLITUS PATIENTS. A CASE-CONTROL STUDY IN ROMANIAN CAUCASIANS PATIENTS.

Persistent inflammation and impaired neovascularization are important contributors to the development of diabetic retinopathy (DR). Gene polymorphisms of adiponectin (APN) were demonstrated to have an important role on the plasma level and activity of adiponectin. APN has anti-inflammatory, anti-diabetic and anti-atherogenic properties. Toll-Like Receptor 4 (TLR4) is a critical mediator of innate immunity. Polymorphisms in TLR-4 gene were shown to be associated with impaired inflammatory response in diabetes. The aim of the study was to analyze the association of +276G>T variant of APN gene and Asp299Gly and Thr399Ile of TLR-4 gene variants in relationship with T2DM and DR in an Eastern European population group. The distribution of the mutant alleles in 198 T2DM patients with DR and 200 non-T2DM controls was examined. Genomic DNA from T2DM patients and healthy controls genotyped through the use of PCR-RFPL assay. Genotype and allele frequencies of the Asp299Gly and Thr399Ile polymorphisms differed between T2DM patients and non diabetic subjects (P<0.001). Moreover, the presence of the minor alleles of these polymorphisms were significantly identified as protective factors against T2DM, under a dominant model of Fisher's exact test (χ2=4.988, phi=0.745, OR=0.767, 95% CI=0.602-0.867, P<0.001; respectively χ2=5.254, phi=0.820, OR=0.487, 95% CI=0.211-0.648, P<0.001). Genotype analysis for the adiponectin 276G>T gene polymorphism yielded no significant association with T2DM, but revealed a borderline significance for the association with DR (χ2=5.632, phi=0.423, OR =1.101, 95% CI=0.887-1.203, P=0.009). We found an association between the TLR4 Asp299Gly and Thr399Ile polymorphisms and protection for DR. The APN genetic polymorphism is not associated with T2DM.

Association of Helicobacter pylori infection with Toll-like receptor-4 Thr399Ile polymorphism increased the risk of peptic ulcer development in North of Iran.

Toll-like receptor-4 (TLR4) polymorphisms may influence host immune response against Helicobacter pylori (H.pylori). This study aimed to investigate whether TLR4 polymorphisms are associated with H.pylori susceptibility and risk of peptic ulcer development or not. The TLR4+3725G/C polymorphism was studied using polymerase chain reaction with confronting two-pair primers (PCR-CTPP). In addition, TLR4 Asp299Gly and Thr399Ile polymorphisms were evaluated by PCR-restriction fragment length polymorphism (RFLP). There was no significant difference in TLR4+3725G/C and Asp299Gly genotype frequencies between non-peptic ulcer (NPUD) and peptic ulcer (PUD) individuals in the context of peptic ulcer development and susceptibility to infection with H.pylori. Nevertheless, a significant association with increased risk for PUD development was observed for polymorphism TLR4 Thr399Ile [odds ratio (OR)=4.2; 95% confidence interval (CI)=1.35-13.26; p=0.01]. Correspondingly, TLR4 Thr399Ile polymorphism was associated with H.pylori susceptibility (OR=0.27; 95% CI=0.08-0.88; p=0.04). In addition, TLR4 Thr399Ile polymorphism increased 4.2-fold, the risk of peptic ulcer development in individuals infected by H.pylori carrying CT+TT genotype. Our results showed that TLR4 Thr399Ile polymorphism along with H.pylori infection may play critical roles in peptic ulcer development in North of Iran.

Association between TLR2 and TLR4 Gene Polymorphisms and the Susceptibility to Inflammatory Bowel Disease: A Meta-Analysis.

BackgroundThe associations between toll-like receptor 2 (TLR2) and toll-like receptor 4(TLR4) polymorphisms and inflammatory bowel disease (IBD) susceptibility remain controversial. A meta-analysis was performed to assess these associations.MethodsA systematic search was performed to identify all relevant studies relating TLR2 and TLR4 polymorphisms and IBD susceptibility. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Subgroup analyses were performed by ethnicity and publication quality.ResultsThirty-eight eligible studies, assessing 10970 cases and 7061 controls were included. No TLR2 Arg677Trp polymorphism was found. No significant association was observed between TLR2 Arg753Gln polymorphism and Crohn’s disease (CD) or ulcerative colitis (UC) in all genetic models. Interestingly, TLR4 Asp299Gly polymorphism was significantly associated with increased risk of CD and UC in all genetic models, except for the additive one in CD. In addition, a statistically significant association between TLR4 Asp299Gly polymorphism and IBD was observed among high quality studies evaluating Caucasians, but not Asians. Associations between TLR4 Thr399Ile polymorphisms and CD risk were found only in the allele and dominant models. The TLR4 Thr399Ile polymorphism was associated with UC risk in pooled results as well as subgroup analysis of high quality publications assessing Caucasians, in allele and dominant models.ConclusionsThe meta-analysis provides evidence that TLR2 Arg753Gln is not associated with CD and UC susceptibility in Asians; TLR4 Asp299Gly is associated with CD and UC susceptibility in Caucasians, but not Asians. TLR4 Thr399Ile may be associated with IBD susceptibility in Caucasians only. Additional well-powered studies of Asp299Gly and other TLR4 variants are warranted.

Toll-like receptor 4 gene polymorphisms and susceptibility to colorectal cancer: a meta-analysis and review.

IntroductionMany case-control studies have investigated the association between toll-like receptor 4 (TLR4) Asp299Gly and Thr399Ile polymorphisms and risk of colorectal cancer (CRC). However, published data are still conflicting.Material and methodsA systematic search was conducted in the electronic databases of PubMed, MEDLINE, EMBASE, Web of Science and CNKI between 2000 and 2014. The associations between TLR4 polymorphisms and CRC susceptibility were assessed by pooled odds ratios (ORs) and 95% confidence intervals (95% CI) in fixed or random effects models.ResultsIn total nine case-control studies were identified in this meta-analysis. For TLR4 Asp299Gly polymorphism, 9 studies included 1198 cases and 1290 controls. The GG genotype carriers had higher risk for developing CRC than AA + GA genotype carriers (OR = 1.95, 95% CI: 1.00–3.77, p = 0.05). No association was found in other genetic models (p > 0.05). Analysis stratified by ethnicity showed no association in any genetic models among the Asian or Caucasian population. For TLR4 Thr399Ile polymorphism, 6 studies contained 619 cases and 632 controls. The overall analysis showed significantly increased risk in TT homozygote carriers compared to CC homozygote (OR = 4.99, 95% CI: 1.41–17.65, p = 0.01) and C carriers (TC + CC) (OR = 4.50, 95% CI: 1.27–15.87, p = 0.02). In terms of analyses stratified by race, a significant association was found in each genetic model among the Asian population, rather than the Caucasian group.ConclusionsThe GG homozygote carriers of TLR4 Asp299Gly and TT homozygote carriers of TLR4 Thr399Ile polymorphisms might be correlated with an increased risk of CRC, suggesting they may serve as genetic risk factors for CRC.

Genomic Analysis of Single Nucleotide Polymorphisms Asp299Gly and Thr399Ile in Japanese Patients with Invasive Aspergillosis.

Single nucleotide polymorphisms (SNPs) 1063A/G (Asp299Gly) and 1363C/T (Thr399Ile) in the gene encoding Toll-like receptor 4 (TLR4) increase susceptibility to invasive aspergillosis. However, limited information is available on the prevalence of these SNPs in Japan. Therefore, we surveyed these TLR4 SNPs by using formalin-fixed and paraffin-embedded tissue blocks obtained from autopsies of patients with invasive pulmonary aspergillosis. Tissue samples of approximately 30% patients were included in genomic analysis. However, none of these samples showed the presence of TLR4 Asp299Gly and Thr399Ile polymorphisms. Thus, the present study provided information on the prevalence of TLR4 SNPs in Japanese patients with invasive aspergillosis and indicated that these SNPs played a minor role in increasing the susceptibility of Japanese individuals to invasive aspergillosis.

Role of TLR4 C&gt;1196T (Thr399Ile) and TLR4 A&gt;896G (Asp299Gly) polymorphisms in a North Indian population with asthma: a case‐control study

Toll-like receptor 4 (TLR4) is the most important TLR among the pattern recognition receptors which recognizes lipopolysaccharide of gram-negative bacteria. They identify a highly conserved structure of microbes called pathogen-associated molecular patterns and activate immune and inflammatory responses that have been shown to be involved in the pathogenesis of asthma. The role of TLR4 gene polymorphisms in asthma was detected in a total of 964 individuals, including 483 healthy controls and 481 asthma patients from a North Indian population. The genotyping was carried out using polymerase chain reaction-restriction fragment length polymorphism method. Statistical analysis revealed that the heterozygous genotype as well as the mutant (T) allele of the TLR4 C>1196T (Thr399Ile) polymorphism shows resistance towards asthma with OR = 0.70, 95% CI (0.49-0.99), P corrected value = 0.046 and OR = 0.72, 95% CI (0.52-0.98), P corrected value = 0.039, respectively. However, no association was found between the TLR4 A>896G (Asp299Gly) polymorphism and asthma patients (P > 0.05). This is the first study conducted in India conferring TLR4 (Thr399Ile) polymorphism resistance towards asthma, while lack of association was found between TLR4 (Asp299Gly) polymorphism and asthma in the studied North Indian population.

Toll-like receptor 4 polymorphisms to determine acute pancreatitis susceptibility and severity: a meta-analysis.

To investigate the correlation of toll-like receptor 4 (TLR4) gene Asp299Gly and Thr399Ile polymorphisms and acute pancreatitis (AP) risk and severity. To get a more precise estimation of the relationship, a comprehensive search was performed to examine all the eligible studies of TLR4 Asp299Gly and Thr399Ile polymorphisms and AP risk. The odds ratios with 95% confidence intervals were used to assess the strength of the association. Publication bias was analyzed by Begg's funnel plots. In total, six studies with 1255 cases and 998 controls were included in this meta-analysis. Totally, no significant associations were found between TLR4 Asp299Gly or Thr399Ile polymorphisms and AP risk using five models with high homogeneity (P > 0.05). Furthermore, stratification analysis by ethnicity or assay also found no significant association in these two polymorphisms (P > 0.05), and TLR4 Asp299Gly was not associated with AP severity (P > 0.05). In addition, no publication bias was found in these studies (P > 0.05). Our current meta-analysis suggests that TLR4 Asp299Gly and Thr399Ile polymorphisms may not be risk factors to AP susceptibility.

Associations Between the Four Toll-Like Receptor Polymorphisms and the Risk of Gastric Cancer: A Meta-Analysis

The association between Toll-like receptor 2 (TLR2) -196 to -174del polymorphism and Toll-like receptor 4 (TLR4) polymorphisms (Asp299Gly, Thr399Ile, and 3725G>C) and gastric cancer risk are still conflicting. For better understanding of the effects of these four polymorphisms on gastric cancer risk, a meta-analysis was performed. An extensive search was performed to identify all case-control studies investigating such associations. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the relationship. A total of 21 studies (3,436 cases and 4,239 controls) were found to be eligible for meta-analysis. In the overall analysis, a significantly increased risk was observed in TLR4 Asp299Gly polymorphism (G allele vs. A allele: OR=1.84, 95%CI: 1.41, 2.39; GA vs. AA: OR=1.89, 95%CI: 1.43, 2.48; Recessive model: OR=1.90, 95%CI: 1.44, 2.49) and TLR4 Thr399Ile polymorphism (T allele vs. C allele: OR=1.97, 95%CI: 1.22, 3.18; TC vs. CC: OR=1.94, 95%CI: 1.19, 3.15; Recessive model: OR=1.98, 95%CI: 1.21, 3.21), whereas no associations were found in any genetic models of TLR2 -196 to -174del and TLR4 3725G>C polymorphisms. Similar results were found in the subgroup analyses by ethnicity. However, we detected that A allele carriers of the TLR4 Asp299Gly polymorphism might have an increase risk of gastric cancer in the Helicobacter pylori-positive population (G allele vs. A allele: OR=2.01, 95%CI: 1.22, 3.31). The results of this meta-analysis indicate that the TLR4 Asp299Gly and Thr399Ile polymorphisms are risk factors for gastric cancer development.

Toll-like receptor 4 polymorphisms and susceptibility to multiple autoimmune diseases: evidence based on pooled analysis

ENWEndNote BIBJabRef, Mendeley RISPapers, Reference Manager, RefWorks, Zotero AMA Wang X, Zhang K, Xiong D. Review paperToll-like receptor 4 polymorphisms and susceptibility to multiple autoimmune diseases: evidence based on pooled analysis. Central European Journal of Immunology. 2013;38(3):380-387. doi:10.5114/ceji.2013.37757. APA Wang, X., Zhang, K., & Xiong, D. (2013). Review paperToll-like receptor 4 polymorphisms and susceptibility to multiple autoimmune diseases: evidence based on pooled analysis. Central European Journal of Immunology, 38(3), 380-387. https://doi.org/10.5114/ceji.2013.37757 Chicago Wang, Xiao-qin, Kui Zhang, and Ding Xiong. 2013. "Review paperToll-like receptor 4 polymorphisms and susceptibility to multiple autoimmune diseases: evidence based on pooled analysis". Central European Journal of Immunology 38 (3): 380-387. doi:10.5114/ceji.2013.37757. Harvard Wang, X., Zhang, K., and Xiong, D. (2013). Review paperToll-like receptor 4 polymorphisms and susceptibility to multiple autoimmune diseases: evidence based on pooled analysis. Central European Journal of Immunology, 38(3), pp.380-387. https://doi.org/10.5114/ceji.2013.37757 MLA Wang, Xiao-qin et al. "Review paperToll-like receptor 4 polymorphisms and susceptibility to multiple autoimmune diseases: evidence based on pooled analysis." Central European Journal of Immunology, vol. 38, no. 3, 2013, pp. 380-387. doi:10.5114/ceji.2013.37757. Vancouver Wang X, Zhang K, Xiong D. Review paperToll-like receptor 4 polymorphisms and susceptibility to multiple autoimmune diseases: evidence based on pooled analysis. Central European Journal of Immunology. 2013;38(3):380-387. doi:10.5114/ceji.2013.37757.

Lack of association between TLR4 Asp299Gly and Thr399Ile polymorphisms and sepsis susceptibility: A meta-analysis

Sepsis, a condition of systemic inappropriate inflammation response to the invasion of microorganisms, results in considerable morbidity and mortality in patients. Some, but not all, epidemiological studies have suggested that Toll-like receptor 4 (TLR4) polymorphisms, Asp299Gly and Thr399Ile, may influence the risk of at-risk patients for sepsis. Our work tried to further study the association of the two common polymorphisms with sepsis susceptibility by performing a meta-analysis of previous data. Electronic searches of MEDLINE, EMBASE and Web of Science databases were performed. Original observational studies dealing with the association between polymorphisms Asp299Gly and/or Thr399Ile and sepsis risk were selected. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with random-effects model or fixed-effects model based on the heterogeneity analysis. Seventeen studies including 2212 cases and 3880 controls were included with most subjects of Caucasian ethnicity. The odds ratio for the association of Asp299Gly polymorphism with sepsis risk was 1.22 (95% CI: 0.90–1.65, P=0.21), and the association of Thr399Ile polymorphism was 1.16 (95%CI: 0.70–1.91, P=0.57). Subgroup analysis and sensitivity analysis did not change the results. Our meta-analysis revealed that the two common TLR4 polymorphisms, Asp299Gly and Thr399Ile, have no strong association with the likelihood of sepsis in Caucasian populations. Further studies are needed to investigate the effect of genetic networks and their mutual interactions in TLR4 signaling pathway on sepsis susceptibility.

TLR4 Asp299Gly and Thr399Ile Polymorphisms: No Impact on Human Immune Responsiveness to LPS or Respiratory Syncytial Virus

BackgroundA broad variety of natural environmental stimuli, genotypic influences and timing all contribute to expression of protective versus maladaptive immune responses and the resulting clinical outcomes in humans. The role of commonly co-segregating Toll-like receptor 4 (TLR4) non-synonymous single nucleotide polymorphisms Asp299Gly and Thr399Ile in this process remains highly controversial. Moreover, what differential impact these polymorphisms might have in at risk populations with respiratory dysfunction, such as current asthma or a history of infantile bronchiolitis, has never been examined. Here we determine the importance of these polymorphisms in modulating LPS and respiratory syncytial virus (RSV) - driven cytokine responses. We focus on both healthy children and those with clinically relevant respiratory dysfunction.MethodologyTo elucidate the impact of TLR4 Asp299Gly and Thr399Ile on cytokine production, we assessed multiple immune parameters in over 200 pediatric subjects aged 7–9. Genotyping was followed by quantification of pro- and anti-inflammatory cytokine responses by fresh peripheral blood mononuclear cells upon acute exposure to LPS or RSV.Principal FindingsIn contrast to early reports, neither SNP influenced immune responses evoked by LPS exposure or RSV infection, as measured by the intermediate phenotype of pro- and anti-inflammatory cytokine responses to these ubiquitous agents. There is no evidence of altered sensitivity in populations with “at risk” clinical phenotypes.Conclusions/SignificanceGenomic medicine seeks to inform clinical practice. Determination of the TLR4 Asp299Gly/Thr399Ile haplotype is of no clinical benefit in predicting the nature or intensity of cytokine production in children whether currently healthy or among specific at-risk groups characterized by prior infantile broncholitis or current asthma.

Association of Toll‐Like Receptor 4 Asp299Gly and Thr399Ile Polymorphisms with Increased Infection Risk in Patients with Advanced HIV‐1 Infection

BACKGROUND. The Toll-like receptor 4 (TLR4) is an essential component of the innate immune response to various microorganisms. We investigated the association between TLR4 polymorphism and the risk of acquiring severe infections, in patients with human immunodeficiency virus (HIV)-1 infection. METHODS. The presence of TLR4 Asp299Gly and Thr399Ile single nucleotide polymorphisms (SNPs) was determined in a cohort of 199 HIV-1 infected patients and evaluated in relation to the occurrence of various infections. RESULTS. One hundred seventy-two patients were homozygous for the wild-type genotype; 22 patients (11%) were heterozygous for both SNPs; 4 were heterozygous for 1 polymorphism; 1 patient was heterozygous for the Asp299Gly SNP and homozygous for the Thr399Ile SNP. Of individuals with a nadir CD4 cell count of <100 cells/mm(3), those who carried both SNPs, compared with those who carried the wild-type genotype, demonstrated a >3-fold increase in the odds ratio (OR) of any serious infection (OR, 6.33 vs OR, 1.83, P = .043). CONCLUSIONS. This study suggests an association between the presence of TLR4 Asp299Gly and Thr399Ile polymorphisms and the occurrence of serious infections in HIV-1 infected patients with a history of nadir CD4 cell count of <100 cells/mm(3).

Lack of association of TLR4 gene Asp299Gly and Thr399Ile polymorphisms with rheumatoid arthritis in Chinese Han population of Yunnan Province

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation of synovium and subsequent joint destruction. Recently, genetic polymorphisms within the toll-like receptor 4 (TLR4) genes have been reported to be associated with RA. To analyze the association between the genetic polymorphisms within TLR4 gene and the susceptibility to RA in Chinese people, two functional variants, Asp299Gly and Thr399Ile, in the TLR4 gene were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing techniques from 213 RA patients and 247 ethnically matched controls. None polymorphisms of Asp299Gly and Thr399Ile were detected in all RA cases and controls, which indicates that there is no relevance between these two SNPs and RA in the Chinese Han population. Further studies with extended single nucleotide polymorphisms (SNP) should be performed.

Association of TLR4 Single-Nucleotide Polymorphisms and Sarcoidosis in Greek Patients

The present study investigates the potential role of Toll-like receptor 4 (TLR4) Asp299Gly and Thr399Ile single-nucleotide polymorphisms (SNPs) as risk factors in the development of sarcoidosis using a novel high-throughput microtiter well-based bioluminometric genotyping assay. One hundred and nineteen Greek patients with sarcoidosis and 209 control subjects were genotyped for the two SNPs of the TLR4 gene. The genotypes observed were in Hardy-Weinberg equilibrium. The heterozygote frequency for both SNPs in sarcoidosis group and control population was 13.4% (16/119) and 10.5% (22/209), respectively. The minor genotype was found to be the same for both sarcoidosis and control groups and similar to that found in other Caucasian populations. No significant association of Asp299Gly and Thr399Ile polymorphisms with increased susceptibility to sarcoidosis was found (p = 0.61 and odds ratio = 1.183). In conclusion, genotype data for the TLR4 Asp299Gly and Thr399Ile polymorphisms in the Greek population were found to be in linkage disequilibrium, and no contribution in the pathogenesis of sarcoidosis was established. Further, in course of the present study, we demonstrated a very simple and sensitive high-throughput bioluminometric assay for genotyping Asp299Gly and Thr399Ile polymorphisms in the TLR4 gene.

Toll-like receptor 4 Asp299Gly and Thr399Ile polymorphisms in gastric cancer of intestinal and diffuse histotypes.

In the present study we investigated the potential role of Toll-like receptor 4 (TLR-4) Asp299Gly and Thr399Ile polymorphisms as risk factors in the development of gastric cancer. TLR-4 Asp299Gly and Thr399Ile polymorphisms were investigated in 171 Italian patients with sporadic gastric cancer and in 151 controls. Unconditional regression (odds ratio and 95% confidence intervals) were used to investigate the association of the studied polymorphisms with gastric cancer. TLR-4 Thr399Ile polymorphism is linked with an increased susceptibility to gastric cancer (P = 0.023 and hazard ratio = 3.62). No significant association for TLR-4 Asp299Gly polymorphism was found. In the subgroup of patients with intestinal-type gastric cancer, a significant risk of gastric cancer was associated with TLR-4 Thr399Ile genotype (P = 0.006). Our results demonstrated that TLR-4 Thr399Ile polymorphism is linked with an increased susceptibility to gastric cancer. An increased risk for intestinal gastric cancer in carriers of the TLR4 Thr399Ile allele was observed. Future epidemiological studies should consider the possible interactions between proinflammatory genotypes (such as TLR and interleukin-1R polymorphisms) and other risk factors for cancer such as dietary habits and/or exposure to environmental carcinogens.

Rarity of TLR4 Asp299Gly and Thr399Ile Polymorphisms in the Korean Population

PurposeActivation of the innate immune system and chronic low-grade inflammation are thought to be involved in the pathogenesis of atherosclerosis and also thought to be associated with type 2 diabetes and its complications. As a receptor for bacterial lipopolysaccharide and heat-shock proteins, Toll-like receptor 4 (TLR4) is one of the central regulators of the immune response. Recent studies have reported an association between TLR4 polymorphisms and diabetes and its complications in Caucasian populations.Materials and MethodsIn this study, we analyzed the association between TLR4 gene polymorphisms in patients with features of type 2 diabetes and healthy controls in Korea. Two polymorphisms of the TLR4 gene (Asp299Gly and Thr399Ile) were examined in 225 diabetic patients and 153 healthy controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and single-strand conformation polymorphism (SSCP).ResultsNo Asp299Gly or Thr399Ile mutations were detected in any of the 378 subjects. Seven subjects from each group who had slightly different SSCP patterns were selected for sequencing, but we found no TLR4 polymorphisms on Exon3. The Asp299Gly and Thr399Ile TLR4 gene polymorphisms were absent in both groups, which was similar to the results for Japanese and Chinese Han subjects.ConclusionOur data and other Asian data suggest that a racial difference can be found in the frequency of the TLR4 polymorphism.

Lack of genetic association of the Toll-like receptor 4 (TLR4) Asp299Gly and Thr399Ile polymorphisms with spondylarthropathies in a Hungarian population

Bacteria have long been suggested as aetiological factors in the genetically susceptible host in spondylarthropathies, including ankylosing spondylitis (AS) and reactive arthritis (ReA). Variability of the Toll-like receptor 4 (TLR4) gene has been shown to play a role in the inflammatory response to certain bacterial infections. We investigated whether TLR4 Asp299Gly and Thr399Ile polymorphisms contribute to the genetic background of spondylarthropathies in a cohort of Hungarian patients with AS and ReA. DNA was obtained from patients with AS (n=138), ReA (n=91) and ethnically matched healthy controls (n=140). Genotyping was carried out by polymerase chain reaction-restriction fragment length polymorphism analysis and the results were confirmed by direct sequencing. No significant differences in allele or genotype frequencies were observed between controls and either the AS patients or the ReA patients. Clinical characteristics of these groups were unrelated to the presence of any of these polymorphisms. Toll-like receptor 4 Asp299Gly and Thr399Ile polymorphisms do not contribute to disease susceptibility in either AS or ReA. Functional abnormalities of the TLR4 signalling pathway suggested in spondylarthropathies seem not to be genetically determined by these two common polymorphisms.

Toll like Receptor 4 Is Involved in In VIvo Antiphospholipid-Mediated Thrombosis and Endothelial Cell Activation.

Background: Antiphospholipid antibodies (aPL) are associated with thrombosis and pregnancy loss in patients with Antiphospholipid Syndrome (APS). aPL and bacterial lipopolysaccharide (LPS) bind to and activate endothelial cells (EC) through NFκB and p38 MAPK pathways. Recent studies suggest that aPL might interact with toll-like receptor-4 (TLR-4), the receptor for LPS.Aim: to investigate the role of TLR-4 in antiphospholipid syndrome (APS).Methods: we examined: i) the aPL effects on thrombosis and EC activation in LPS non-responsive (LPS−/−) mice that display a spontaneous mutation of TLR-4 vs LPS-responsive (LPS+/+) mice displaying wild type TLR-4, ii) the prevalence of TLR-4 Asp299gly and Thr399Ile polymorphisms - both associated with decreased response to LPS - in 110 APS patients (with arterial and/or venous thrombosis) vs 220 controls (of same ethnic background). IgGs were purified from a patient with APS (IgG-APS) and from control serum (IgG-NHS). LPS −/− and LPS +/+ mice, in groups of nine, were treated with IgG-APS or with IgG-NHS twice intraperitoneally. Size of induced thrombi and # of leukocyte (WBC) adhering to endothelial cells in the microcirculation of endothelium of the cremaster muscle of mice (as a means to measure endothelial cell activation) were determined in vivo, seventy-two hours after the first injection. TLR-4 Asp299gly & Thr399Ile polymorphisms were evaluated by Allele-Specific PCR.Results: LPS +/+ mice treated with IgG-APS produced significantly larger thrombi when compared to mice treated with IgG-NHS (2166 ± 1419 μm2 vs 1176 ± 841 μm2) and significantly larger number of WBC adherence to ECs (4.5 ± 1.9 vs 2.2 ±1.1). Thrombus size and number of adhering WBC to ECs were significantly lower in LPS −/− mice treated with IgG-APS compared to LPS +/+ mice treated with IgG-APS [thrombus size: 779 ± 628 μm2 vs 2166 ± 1419 μm2 (p<0.05) and number of adherent WBC to EC: 1.0 ± 0.5 vs 4.5 1.9 (p<0.05)], respectively. The titer of anticardiolipin antibodies in the sera of mice injected with aPL was 48.2 ± 17.1 GPL (for LPS −/− mice) and 50.8 ± 11.2 GPL (for LPS +/+ mice), respectively (NS). A significant reduction in TLR-4 Asp 299gly & Thr399Ile polymorphisms was observed in APS patients (5%) compared to controls (11.4%) (p<0.05).Conclusions: These findings strongly suggest that TLR-4 is involved in aPL interaction with endothelial cells and mediates their pathogenic effects.