Polymorphism in 3'-untranslated region of toll-like receptor 4 gene is associated with protection from hepatitis B virus recurrence after liver transplantation

Recent advances in different interactions between toll-like receptors and hepatitis B infection: a review

Hepatitis B virus (HBV) B infections remain a primary global health concern. The immunopathology of the infection, specifically the interactions between HBV and the host immune system, remains somewhat unknown. It has been discovered that innate immune reactions are vital in eliminating HBV. Toll-like receptors (TLRs) are an essential category of proteins that detect pathogen-associated molecular patterns (PAMPs). They begin pathways of intracellular signals to stimulate pro-inflammatory and anti-inflammatory cytokines, thus forming adaptive immune reactions. HBV TLRs include TLR2, TLR3, TLR4, TLR7 and TLR9. Each TLR has its particular molecule to recognize; various TLRs impact HBV and play distinct roles in the pathogenesis of the disease. TLR gene polymorphisms may have an advantageous or disadvantageous efficacy on HBV infection, and some single nucleotide polymorphisms (SNPs) can influence the progression or prognosis of infection. Additionally, it has been discovered that similar SNPs in TLR genes might have varied effects on distinct populations due to stress, diet, and external physical variables. In addition, activation of TLR-interceded signaling pathways could suppress HBV replication and increase HBV-particular T-cell and B-cell reactions. By identifying these associated polymorphisms, we can efficiently advance the immune efficacy of vaccines. Additionally, this will enhance our capability to forecast the danger of HBV infection or the threat of dependent liver disease development via several TLR SNPs, thus playing a role in the inhibition, monitoring, and even treatment guidance for HBV infection. This review will show TLR polymorphisms, their influence on TLR signaling, and their associations with HBV diseases.

Association between TLR2, TLR4, and TLR5 genetic variants and the risk of hepatocellular carcinoma in Moroccan population

Hepatocellular carcinoma (HCC) is the fifth most common human malignancy and the fourth most frequent cause of cancer-related deaths worldwide. Toll-like receptors (TLRs), are known to play a key role in hepatocarcinogenesis through induction of inflammation. We aimed to investigate the association between TLR2 rs3804099, TLR4 rs4986790, rs4986791, and rs11536889 and TLR5 rs5744174 and HCC risk in a total of 306 Moroccan subjects, including 152 HCC patient and 154 controls using a TaqMan allelic discrimination assay. Our result showed that the frequency of TLR4 rs11536889 C allele was higher in control group than in HCC patients (OR = 0.52, 95% CI = 0.30-0.88, p = 0.01). Moreover, under the dominant model, we observed that CG/CC genotypes were protective factors against HCC risk (OR = 0.51, 95% CI = 0.28-0.91, p = 0.02). However, no significant differences were found in the allele and genotype frequencies of TLR4 rs4986790 and rs4986791, between HCC patients and controls. Similarly, genotypic frequencies of TLR2 and TLR5 polymorphisms did not differ significantly between HCC patients and controls. However, TLR4 haplotype analysis revealed that ACC haplotype may be protective of HCC risk in patients with HCC (OR = 0.53, 95% CI = 0.31-0.92, p = 0.02). In conclusion, our result suggest that TLR4 rs11536889 polymorphism and ACC haplotype may decrease risk of hepatocellular carcinoma in Moroccan population.

Association of toll-like receptors single nucleotide polymorphisms with HBV and HCV infection: research status

Background

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections have become increasingly severe worldwide and are a threat to public health. There have been a number of studies conducted recently on the relationship of single nucleotide polymorphisms (SNPs) to innate immune receptor genes such as toll-like receptors (TLRs). Some literature suggests that SNPs of TLRs are associated with HBV and HCV infection. We summarized the role of TLRs gene polymorphisms associated with HBV and HCV infections and explored their possible mechanisms of action.

Methodology

PubMed and Web of Science were used to perform the literature review. Related articles and references were identified and used to analyze the role of TLRs gene polymorphism in HBV and HCV infection.

Results

TLRs gene polymorphisms may have beneficial or detrimental effects in HBV and HCV infection, and some SNPs can affect disease progression or prognosis. They affect the disease state by altering gene expression or protein synthesis; however, the mechanism of action is not clearly understood.

Conclusions

Single nucleotide polymorphisms of TLRs play a role in HBV and HCV infection, but the mechanism of action still needs to be explored in future studies.

Association of TLR4 and TLR9 gene polymorphisms and haplotypes with cervicitis susceptibility

BACKGROUND

Cervicitis is one of the major health problems amongst women caused by infection of various pathogens including Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Trichomonas vaginalis (TV) as well as human papillomavirus (HPV), and persistent cervical inflammation is one of the etiologic agents of cervical cancer. Toll-like receptors (TLRs) play an important role in the recognition and subsequent elimination of these pathogens. Variations in the Toll-like receptor genes influence susceptibility to pathogens as well as disease progression independently.

METHODS

Ten single nucleotide polymorphisms, five each of TLR4 and TLR9 genes were analyzed among 130 cervicitis patients and 150 controls either using polymerase chain reaction-restriction fragment length polymorphism or allele specific-PCR.

RESULTS

T. vaginalis infection was found at the highest frequency (30.7%) as compared to C. trachomatis (1.5%), N. gonorrhoeae (2.3%) and HPV (4.6%) infections in cervicitis patients. TLR4 rs11536889 CC (age-adjusted OR, 2.469 [95% CI, 1.499 to 4.065]; p < 0.001) and TLR9 rs187084 TC (age-adjusted OR, 2.165 [95% CI, 1.267-3.699]; p = 0.005) genotypes showed the higher distribution in cervicitis patients compared to controls. In addition, TLR4 rs11536889 C allele was shown to increase the risk of cervicitis (age-adjusted OR, 1.632 [95% CI, 1.132 to 2.352]; p = 0.009) compared to controls. The TLR4 haplotype GCA (OR, 0.6 [95% CI, 0.38-0.95]; p = 0.0272) and TLR9 haplotype GTA (OR, 1.99 [95% CI, 1.14-3.48]; p = 0.014) were found to be associated with decreased and increased risk of cervicitis respectively.

CONCLUSIONS

TLR4 and TLR9 polymorphisms, as well as haplotypes were shown to modulate the cervicitis risk.

Toll-like receptor genetic variations in bone marrow transplantation

The Toll-like receptor family mediates the innate immune system through recognizing the molecular patterns of microorganisms and self-components and leading the synthesis of the inflammatory mediators. We retrospectively examined whether or not genetic variations in toll-like receptor 1 (rs5743551, -7202GQ>A), toll-like receptor 2 (rs7656411, 22215G>T), and toll-like receptor 4 (rs11536889, +3725G>C) affected transplant outcomes in a cohort of 365 patients who underwent unrelated HLA-matched bone marrow transplantation (for hematologic malignancies through the Japan Marrow Donor Program. Only donor toll-like receptor 4 variation significantly improved the survival outcomes. A multivariate analysis showed that the donor toll-like receptor 4 +3725G/G genotype was significantly associated with a better 5-year progression-free survival and a lower 5-year transplant-related mortality than other variations. Furthermore, the donor toll-like receptor 4 +3725G/G genotype was associated with a significantly lower incidence of fatal infections than other variations. The validation study of 502 patients confirmed that the donor toll-like receptor 4 +3725G/G genotype was associated with better survival outcomes. Toll-like receptor4 genotyping in transplant donors may therefore be a useful tool for optimizing donor selection and evaluating pretransplantation risks.

The association between donor genetic variations in one-carbon metabolism pathway genes and hepatitis B recurrence after liver transplantation

BACKGROUNDS AND AIM

Hepatitis B recurrence adversely affects patients' survival after liver transplantation. This study aims to find association between donor gene variations of one carbon metabolism and post-transplant hepatitis B recurrence.

METHODS

This study enrolled 196 patients undergoing liver transplantation for HBV related end-stage liver diseases. We detected 11 single nucleotide polymorphisms (SNP) of 7 one-carbon metabolism pathway genes (including MTHFR, MTR, MTRR, ALDH1L1, GART, SHMT1 and CBS) in donor livers and analyzed their association with HBV reinfection after liver transplantation.

RESULTS

Hepatitis B recurrence was observed in 19 of the 196 patients (9.7%) undergoing liver transplantation. Hepatitis B recurrence significantly affected post-transplant survival in the 196 patients (p = 0.018), and correlate with tumor recurrence in the subgroup of HCC patients (n = 99, p = 0.006). Among the 11 SNPs, donor liver mutation in rs1979277 (G > A) was adversely associated with post-transplant hepatitis B recurrence (p = 0.042). In the subgroup of HCC patients, survival analysis showed donor liver mutations in rs1801133 (G > A) and rs1979277 (G > A) were risk factors for hepatitis B recurrence (p < 0.05). None of the 11 SNPs was related to hepatitis B recurrence in non-HCC patients (n = 97, p > 0.05).

CONCLUSION

Hepatitis B recurrence impaired post-transplant survival. Donor liver genetic variations in one-carbon metabolism pathway genes were significantly associated with post-transplant hepatitis B recurrence.

Toll like receptor 4 and hepatocellular carcinoma; A systematic review

INTRODUCTION

Toll like receptor 4 (TLR4) is an extracellular pathogen recognition receptor (PRR) which recognizes a wide range of pathogens and damage associated molecular patterns (PAMPs and DAMPs). It can activate intracellular signaling and consequently transcription factors which participate in transcription from either immune related or malignancy genes. Thus, it has been hypothesized that TLR4 may be a cause of hepatocellular carcinoma (HCC). This article has reviewed the roles of TLR4 in the pathogenesis of HCC.

METHOD

"TLR4", "hepatocellular carcinoma", "liver tumor" and "liver cancer" were used as key words for searching in Scopus, Google Scholar and MEDLINE scientific databases.

RESULTS

Most of the investigations documented the roles of TLR4 in induction of HCC via several mechanisms including increased number of T regulatory lymphocytes and liver resident follicular helper like cells, increased production of pro-inflammatory and malignancy related molecules including cytokines, NANOG, Caspase-1, Ephrin-A1, NO and BCL6. TLR4 participates in the proliferation of the cells and also production of the molecules in both chronic infectious and non-infectious inflammatory diseases.

DISCUSSION

TLR4 is an innate immunity receptor which plays a pathogenic role during chronic inflammation and can induce HCC in human.

Polymorphisms in TCF7L2 gene are associated with gestational diabetes mellitus in Chinese Han population

This study aimed to investigate the possible association between diabetes susceptibility gene transcription factor 7-like 2 (TCF7L2) and gestational diabetes mellitus (GDM) in a Chinese Han population. A total of 556 GDM patients and 500 Non-GDM were included. Eighteen single nucleotide polymorphisms (SNPs) were evaluated. Fifteen tag SNPs were selected from HapMap CHB database with a minor allele frequency of >0.2 and r² of >0.8. Three additional SNPs were also chosen because these SNPs are associated with type 2 diabetes in East Asians. TCF7L2 rs290487, rs6585194, and rs7094463 polymorphisms were found to be significantly associated with GDM. In multivariate analysis, rs290487 genetic variation (OR = 2.686 per each C allele, P = 0.002), pre-BMI > 24 kg/m² (OR = 1.592, P = 0.018), age > 25 years (OR = 1.780, P = 0.012) and LDL-C > 3.6 mmol/L (OR = 2.034, P = 0.009) were identified as independent risk factors of GDM, rs7094463 genetic variation (OR = 0.429 per each G allele, P = 0.005) was identified as independent protect factor of GDM. This finding suggests that TCF7L2 rs290487, and rs7094463 were a potential clinical value for the prediction of GDM.

Single nucleotide polymorphisms/haplotypes associated with multiple rubella-specific immune response outcomes post-MMR immunization in healthy children

The observed heterogeneity in rubella-specific immune response phenotypes post-MMR vaccination is thought to be explained, in part, by inter-individual genetic variation. In this study, single nucleotide polymorphisms (SNPs) and multiple haplotypes in several candidate genes were analyzed for associations with more than one rubella-specific immune response outcome, including secreted IFN-γ, secreted IL-6, and neutralizing antibody titers. Overall, we identified 23 SNPs in 10 different genes that were significantly associated with at least two rubella-specific immune responses. Of these SNPs, we detected eight in the PVRL3 gene, five in the PVRL1 gene, one in the TRIM22 gene, two in the IL10RB gene, two in the TLR4 gene, and five in other genes (PVR, ADAR, ZFP57, MX1, and BTN2A1/BTN3A3). The PVRL3 gene haplotype GACGGGGGCAGCAAAAAGAAGAGGAAAGAACAA was significantly associated with both higher IFN-γ secretion (t-statistic 4.43, p < 0.0001) and higher neutralizing antibody titers (t-statistic 3.14, p = 0.002). Our results suggest that there is evidence of multigenic associations among identified gene SNPs and that polymorphisms in these candidate genes contribute to the overall observed differences between individuals in response to live rubella virus vaccine. These results will aid our understanding of mechanisms behind rubella-specific immune response to MMR vaccine and influence the development of vaccines in the future.

Polymorphisms of FGFR1 in HBV-related hepatocellular carcinoma

Hepatitis B virus (HBV)-induced hepatocellular carcinoma (HCC) is one of the most commonly diagnosed cancers in China. It is important to understand the genetic mechanisms underlying the development and progression of HBV-related HCC and to identify new biomarkers for clinical treatment. The important role of fibroblast growth factor receptors (FGFRs) has been widely recognized in many types of cancers, but the association between FGFR polymorphisms and HCC carcinogenesis has been rarely reported. In this study, 199 patients with HBV-associated cirrhosis, 203 with HBV-associated HCC, and 184 healthy controls with no liver diseases were enrolled as participants. Using SNaPshot assays, five SNPs (rs13317, rs7825208, rs1047057, rs1047111, and rs1966265) of growth factor receptor genes were genotyped. Our results showed that the G/A and G/G genotypes at rs7825208 of FGFR1 were negatively correlated with HBV-related HCC (odds ratio (OR) = 0.45, 95% confidence interval (CI) = 0.22-0.93, P = 0.027). However, after Bonferroni correction, these significant differences no longer existed (P > 0.05). Our results indicated that these five polymorphisms of fibroblast growth factor receptor genes do not play any independent roles in the tumorigenesis and progression of HBV-related HCC in Han Chinese patients.

The association of polymorphisms of TLR4 and CD14 genes with susceptibility to sepsis in a Chinese population

Background

Sepsis is now the leading cause of death in the non-cardiovascular intensive care unit (ICU). Recent research suggests that sepsis is likely to be due to an interaction between genetic and environmental factors. Genetic mutations of toll-like receptor 4 (TLR4) and cluster of differentiation 14 (CD14) genes are involved in the immune and (or) inflammatory response. These may contribute to the susceptibility to sepsis in patients. This study was designed to evaluate whether the TLR4 and cluster CD14 gene polymorphisms are associated with susceptibility to sepsis.

Methods

The single nucleotide polymorphisms (SNPs) of TLR4 (rs10759932, rs11536889, rs7873784, rs12377632, rs1927907, rs1153879) and CD14 (rs2569190 and rs2563298) in patients with sepsis and control subjects in the Guangxi Province were analyzed by using the polymerase chain reaction-single base extension (PCR-SBE) and DNA sequencing methods.

Results

The rs11536889 polymorphism in TLR4 and rs2563298 polymorphism in CD14 were significantly associated with the risk of sepsis when compared to the control group. The frequencies of rs11536889 and rs2563298 polymorphisms in the group with sepsis were higher than that in the control group (OR = 1.430, 95% CI, 1.032-1.981, P<0.05; OR = 2.454, 95% CI, 1.458-4.130, P<0.05, respectively). Followed up haplotype analysis suggested that there were two haplotypes in which increased risk factors for sepsis were indicated.

Conclusions

The rs11536889 polymorphism in TLR4 and rs2563298 polymorphism in CD14, and two haplotypes were associated with increased susceptibility to sepsis.

Toll-like receptor 4 and hepatitis B infection: molecular mechanisms and pathogenesis

Hepatitis B virus (HBV) infection mainly causes liver disease, including inflammation, cirrhosis, and hepatocellular carcinoma (HCC). It has been documented that prolonged hepatitis B-infected patients are unable to clear HBV from hepatocytes completely. Previous investigations have suggested that various genetic and immunologic parameters may be responsible for the induction of prolonged infection forms. Toll-like receptors (TLRs), as members of pathogen recognition receptors (PRRs), play critical roles in the recognition of viruses and the induction of appropriate immune responses. Thus, TLRs may be considered as essential sensors for the recognition of HBV and the induction of immune responses against this virus. It has been documented that TLR4 plays key roles in the detection of several microbial pathogen-associated molecular pattern molecules, including bacterial lipopolysaccharide (LPS), as well as endogenous ligands (damage-associated molecular pattern molecules) and subsequently activates pro-inflammatory transcription factors in either MYD88 or TRIF dependent pathways. Previous investigations have proposed that TLR4 might be involved in appropriate immune responses against HBV. Therefore, the aim of this review is to present the recent data regarding the important roles of TLR4 in HBV recognition and regulation of immune responses against this virus, and also its roles in the pathogenesis of cirrhosis and HCC as complications of prolonged hepatitis B infections.

The regulatory toll-like receptor 4 genetic polymorphism rs11536889 is associated with renal, coagulation and hepatic organ failure in sepsis patients

BACKGROUND

Toll-like receptor 4 (TLR4), a lipopolysaccharide (LPS) receptor complex signal-transducing molecule, plays a crucial role in sensing LPS from gram-negative bacteria. TLR4 signaling pathway activation by LPS plays a major role in sepsis pathogenesis. A single nucleotide polymorphism, rs11536889, in the 3'-untranslated region of the TLR4 gene is thought to affect TLR4 translation. This study aimed to investigate whether organ failure in sepsis patients is related to the TLR4 rs11536889 genotype.

METHODS

Adult Caucasian patients with sepsis from the intensive care unit of a university medical center were followed up for 90 days, and organ failure was recorded as the primary outcome variable. Blood samples were collected at enrollment for TLR4 rs11536889 genotyping. Sepsis-related organ failure assessment (SOFA) scores were quantified at sepsis onset and throughout the observational period to monitor organ failure.

RESULTS

A total of 210 critically ill patients with sepsis were enrolled into this study. Wild-type GG was compared to GC/CC. During their stay in the intensive care unit, GG patients presented significantly higher SOFA scores than did C allele carriers (7.9 ± 4.5 and 6.8 ± 4.2, respectively; p = 0.0005). Analysis of organ-specific SOFA sub-scores revealed significant differences in three organ systems: renal, coagulation and hepatic (p = 0.0005, p = 0.0245 and p < 0.0001, respectively). Additionally, the rs11536889 polymorphism was associated with a higher incidence of gram-negative infections.

CONCLUSIONS

These results offer the first evidence that TLR4 rs11536889 is a useful marker of organ failure in patients with sepsis.

Expression of pattern recognition receptors in cholesteatoma

Although many immunologic mechanisms have been investigated in studies of the pathogenesis of cholesteatoma, the role of pattern recognition receptors (PRRs) has not been fully determined. Therefore, we assessed innate immune responses in patients with cholesteatoma. We prospectively evaluated 21 patients with acquired cholesteatoma between August 2010 and July 2012. Cholesteatoma specimens were obtained during surgery, and skin from the external meatus of each patient was used as a control. RNA was extracted from these tissue samples, followed by real-time PCR to quantitatively assess the relative expression of toll-like receptors (TLRs), NOD-like receptors (NLRs), retinoic acid-inducible gene (RIG)-I, NO synthase (NOS) and cytokines. The levels of TLR-2, -3, -4, -6, -7, and -10, NOD-2, and IL-1 and -8 mRNAs were significantly higher in the cholesteatoma than in the skin specimens (p < .05). The expression levels of TLR-2 and -3, RIG-I, IL-6, and TNF-α mRNAs were significantly higher in cholesteatomas from women than from men. The levels of TLR-8, NOD-2, IL-12, and TNF-α mRNAs were significantly higher in recurrent than in initial cholesteatoma specimens (p < .05). Hearing level did not correlate with the levels of expression of mRNAs encoding TLRs, NLRs, NOS, RIG-I and related cytokines (p > .05). In conclusion, alterations in innate immunity triggered by PRRs are important in the pathophysiology of cholesteatoma. Gender differences and frequency of surgery may affect the expression of PRRs in cholesteatomas.

Polymorphisms in TLR-2 are associated with congenital cytomegalovirus (CMV) infection but not with congenital CMV disease

BACKGROUND

Cytomegalovirus (CMV) is the most common cause of congenital virus infection. However, the risk factors for infection in utero and for progression to a severe clinical outcome remain uncertain. Recent studies have identified associations of specific single nucleotide polymorphisms (SNPs) in Toll-like receptor (TLR) genes with susceptibility to infections of some viruses and with their clinical outcome.

METHODS

Genetic polymorphisms in the TLR-2, TLR-4, and TLR-9 genes were analyzed in 87 children with congenital CMV infections by the TaqMan allelic discrimination assay. The frequencies of genotypes in the general Japanese population were obtained from the National Center for Biotechnology Information (NCBI) databases. Associations between the analyzed SNPs and congenital CMV infection or disease were evaluated.

RESULTS

The CC genotype at SNP rs3804100 in the TLR-2 gene was significantly associated with congenital CMV infection but not with congenital CMV disease. Furthermore, the AG genotype at SNP rs1898830 in the TLR-2 gene tended to be identified less frequently in children with congenital CMV infection. There were no statistically significant associations between SNPs in the TLR-4 and TLR-9 genes and congenital CMV infection or disease.

CONCLUSION

TLR-2 polymorphisms may have some association with congenital CMV infection, although the mechanism underlying this effect remains to be clarified.

Association between donor and recipient TCF7L2 gene polymorphisms and the risk of new-onset diabetes mellitus after liver transplantation in a Han Chinese population

BACKGROUNDS & AIMS

New-onset diabetes mellitus (NODM) is a frequent and serious complication arising after liver transplantation (LT). Transcription factor 7-like 2 (TCF7L2) polymorphisms have been reported to strongly associate with type 2 diabetes. In addition, the donor liver plays a vital role in regulating blood glucose levels. In this study, we aim at evaluating the association between donor and recipient TCF7L2 gene polymorphisms with NODM after LT.

METHODS

A total of 125 patients undergoing primary LT, without a history of diabetes were included. Four single nucleotide polymorphisms (rs290487, rs7903146, rs11196205, and rs12255372), closely associated with type 2 diabetes in the Eastern Asia population, were genotyped and analyzed.

RESULTS

Both donor and recipient rs290487 polymorphisms (CC vs. TT genotype) were found to be significantly associated with NODM. In multivariate analysis, donor rs290487 genetic variation (OR = 2.172 per each C allele, p = 0.015), blood tacrolimus levels at 1 month post-LT >10 ng/ml (OR = 3.264, p = 0.017), and recipient age >55 years (OR = 2.638, p = 0.043) were identified as independent risk factors of NODM. Furthermore, donor rs290487 CC genotype could predict a high probability (>40%) of the onset of NODM. Predictive model containing donor rs290487 polymorphism showed a significantly higher prognostic ability on NODM than the model with only clinical parameters (p = 0.031).

CONCLUSIONS

Donor TCF7L2 rs290487 polymorphism is associated with an increased risk of NODM after LT and has a potential clinical value for the prediction of NODM.

Theoretical basis of a beneficial role for vitamin D in viral hepatitis

Abnormal bone metabolism and dysfunction of the calcium-parathyroid hormone-vitamin D axis have been reported in patients with viral hepatitis. Some studies suggested a relationship between vitamin D and viral hepatitis. Genetic studies have provided an opportunity to identify the proteins that link vitamin D to the pathology of viral hepatitis (i.e., the major histocompatibility complex class II molecules, the vitamin D receptor, cytochrome P₄₅₀, the renin-angiotensin system, apolipoprotein E, liver X receptor, toll-like receptor, and the proteins regulated by the Sp1 promoter gene). Vitamin D also exerts its effects on viral hepatitis via non-genomic factors, i.e., matrix metalloproteinase, endothelial vascular growth factor, prostaglandins, cyclooxygenase-2, and oxidative stress. In conclusion, vitamin D could have a beneficial role in viral hepatitis. Calcitriol is best used for viral hepatitis because it is the active form of the vitamin D₃ metabolite.

Toll-like receptor 4 gene polymorphisms and susceptibility to bladder cancer

Bladder cancer is one of the most common malignancies in the world. Toll-like receptor 4 (TLR4) plays important roles in regulating innate immunity and may affect the development of cancers. Polymorphisms in TLR4 gene have been shown to be associated with impaired immune responses. Here, we investigated the association of TLR4 polymorphisms with bladder cancer. Four TLR4 polymorphisms (-2242T/C, Asp299Gly, Thr399Il3, and +3725G/C) were genotyped in a total number of 436 bladder cancer patients and 522 healthy controls. Data were analyzed using the Chi-square test. Results showed that the prevalence of TLR4 +3725GC and CC genotypes were significantly increased in bladder cancer cases than in controls (odds ratio [OR] = 1.58, 95 % confidence interval [CI] = 1.19-2.10, p = 0.0015, and OR = 2.33, 95%CI = 1.52-3.58, p < 0.0001, respectively). Also, the frequency of TLR4 +3725C allele was significantly higher in bladder cancer patients (p < 0.0001). The -2242T/C, Asp299Gly and Thr399Il3 polymorphisms did not reveal any significant differences between cases and controls. Stratification analysis of the clinical features in the patients demonstrated that cases with invasive cancer were correlated with higher numbers of +3725GC and CC genotype (p = 0.0004 and p = 0.0231). In conclusion, these results indicate that TLR4 +3725G/C polymorphism may be a novel risk factor for bladder cancer in the Chinese population.

A single nucleotide polymorphism in 3'-untranslated region contributes to the regulation of Toll-like receptor 4 translation

We have previously shown that a single nucleotide polymorphism rs11536889 in the 3'-untranslated region (UTR) of TLR4 was associated with periodontitis. In this study the effects of this single nucleotide polymorphism on Toll-like receptor (TLR) 4 expression were investigated. Monocytes from subjects with the C/C genotype expressed higher levels of TLR4 on their surfaces than those from subjects with the other genotypes. Peripheral blood mononuclear cells (PBMCs) from the C/C and G/C subjects secreted higher levels of IL-8 in response to lipopolysaccharide (LPS), a TLR4 ligand, than the cells from the G/G subjects. However, there was no significant difference in TLR4 mRNA levels in PBMCs from the subjects with each genotype. After stimulation with tripalmitoylated CSK(4) (Pam(3)CSK(4)), TLR4 mRNA levels increased in PBMCs from both the C/C and G/G subjects, whereas TLR4 protein levels increased in PBMCs from the C/C but not G/G subjects. Transient transfection of a series of chimeric luciferase constructs revealed that a fragment of 3'-UTR containing rs11536889 G allele, but not C allele, suppressed luciferase activity induced by LPS or IL-6. Two microRNAs, hsa-miR-1236 and hsa-miR-642a, were predicted to bind to rs11536889 G allele. Inhibition of these microRNAs reversed the suppressed luciferase activity. These microRNA inhibitors also up-regulated endogenous TLR4 protein on THP-1 cells (the G/G genotype) after LPS stimulation. Furthermore, mutant microRNAs that bind to the C allele inhibited the luciferase activity of the construct containing the C allele. These results indicate that genetic variation of rs11536889 contributes to translational regulation of TLR4, possibly by binding to microRNAs.

Polymorphisms of toll-like receptors and their pathways in viral hepatitis

Toll-like receptors (TLRs) are an important part of the innate immune response to a variety of pathogens including hepatic viral infections. Activation of TLRs stimulates a complex intracellular signalling cascade that results in production of proinflammatory cytokines and interferons important for antiviral responses as well as induction of the adaptive arm of the immune system. There is substantial evidence for an important role for TLRs and TLR-mediated signalling in the pathogenesis and outcomes of hepatitis B and C in particular, but it might also influence responses to other viral hepatitis infections. Several single nucleotide polymorphisms (SNPs) of TLRs, relevant adaptor molecules and cytokines mediated by TLR signalling have been described that alter innate immune responses and have been implicated in a variety of human diseases including viral and other infections. There is now significant evidence that a number of TLR SNPs can affect various clinical outcomes in Caucasian patients with chronic HCV. However, the role of these polymorphisms in acute and other chronic hepatitis infections, including HBV as well as in non-Caucasian populations, has not been elucidated. In addition, results for SNPs downstream of TLR activation, such as in relevant cytokines, are inconsistent and their influence requires further investigation to determine the clinical significance of genetic variations in these mediators.