Toll-like receptor 7 variations are associated with the susceptibility to HCV infection among Chinese females

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.

IL28B, TLR7 SNPs, and cytomegalovirus infection are risk factors for advanced liver disease in chronic hepatitis C patients

BACKGROUND

Chronic hepatitis C (CHC) is a leading cause of cirrhosis and hepatocellular carcinoma (HCC). This study aimed to study the association of IL28B, toll-like receptor (TLR) 7, cytomegalovirus and advanced liver disease.

METHODS

Four groups were included; control (n = 125, 25.9%), CHC (n = 114, 23.6%), liver cirrhosis (n = 120, 24.8%), and HCC (n = 124, 25.7%).

RESULTS

In CHC group, patients were mainly F1 (60%) followed by F2. IL28B genotype CC percentage was higher in control group than the CHC and cirrhosis groups. CT and TT genotypes were higher in the CHC and cirrhosis groups than control group. The C allele was higher in the control group than the CHC, cirrhosis and HCC groups and the opposite with the T allele. Control and CHC had same TLR7 alleles. Cirrhosis patients and HCC had lower TLR 7 A allele and higher G allele than the control group. Both cirrhosis and HCC groups had statistically significant higher percentage of the AG and GG genotypes than the control group. Patients with HCC had higher cytomegalovirus infection percentage than cirrhosis and CHC group (38.7% vs 20% vs 16.7%), respectively.

CONCLUSION

IL28B, TLR7 SNPs and cytomegalovirus infection are risk factors for advanced liver disease in hepatitis C patients.

Germline Genetic Variants of Viral Entry and Innate Immunity May Influence Susceptibility to SARS-CoV-2 Infection: Toward a Polygenic Risk Score for Risk Stratification

The ongoing COVID-19 pandemic caused by the novel coronavirus, SARS-CoV-2 has affected all aspects of human society with a special focus on healthcare. Although older patients with preexisting chronic illnesses are more prone to develop severe complications, younger, healthy individuals might also exhibit serious manifestations. Previous studies directed to detect genetic susceptibility factors for earlier epidemics have provided evidence of certain protective variations. Following SARS-CoV-2 exposure, viral entry into cells followed by recognition and response by the innate immunity are key determinants of COVID-19 development. In the present review our aim was to conduct a thorough review of the literature on the role of single nucleotide polymorphisms (SNPs) as key agents affecting the viral entry of SARS-CoV-2 and innate immunity. Several SNPs within the scope of our approach were found to alter susceptibility to various bacterial and viral infections. Additionally, a multitude of studies confirmed genetic associations between the analyzed genes and autoimmune diseases, underlining the versatile immune consequences of these variants. Based on confirmed associations it is highly plausible that the SNPs affecting viral entry and innate immunity might confer altered susceptibility to SARS-CoV-2 infection and its complex clinical consequences. Anticipating several COVID-19 genomic susceptibility loci based on the ongoing genome wide association studies, our review also proposes that a well-established polygenic risk score would be able to clinically leverage the acquired knowledge.

Effects of TLR7 Polymorphisms on the Susceptibility and Progression of HIV-1 Infection in Chinese MSM Population

Toll-like receptor (TLR) 7 plays a key role in innate and adaptive immunity for HIV-1 infection. We evaluated the effect of TLR7 polymorphisms on disease susceptibility and progression of HIV-1 infection in Chinese MSM (men who have sex with men). Blood samples were taken from 270 patients with laboratory confirmed HIV infection, 196 male controls were tested, and three TLR7 intronic polymorphisms (rs179010-C > T, X:12884766; rs2074109-T > C, X:12885330; and rs179009-A > G, X:12885361) were analyzed by PCR-based sequencing. The frequency of TLR7 rs179010 T allele was significantly lower in MSM patients than in controls (P = 0.039). The haplotype TTA was associated with a decreased susceptibility to HIV-1 infection (P = 0.013), especially to acute HIV-1 infection (AHI) (P = 0.002), but not to chronic HIV-1 infection (CHI). Furthermore, the haplotype TTA is linked to slow disease progression in AHI patients (P = 0.002) and a lower viral load (P = 0.042). In contrast, TLR7 rs179009 allele A contributed to a higher set point in AHI patients with rapid progression, and the frequency of rs179009 minor allele G was over-presented in CHI patients. This finding supports a role for genetic variations of TLR7 in susceptibility and disease progression of an HIV-1 infection in Chinese Han population and warrants further studies on the effect of TLR7 polymorphisms on HIV-1 infection in different populations.

PNPLA3 polymorphisms are associated with raised alanine aminotransferase levels in hepatitis C virus genotype 3

BACKGROUND AND STUDY AIMS

Hepatitis C virus (HCV) infection is one of the leading causes of end-stage liver diseases. This study aimed to determine the association between polymorphisms in interleukin 28B (IL28B), PNPLA3, toll-like receptor 7 (TLR7), nucleotide-binding oligomerization domain-containing protein 2 (NOD2) and retinoic inducible gene-I (RIG-I) and HCV genotype and clinical presentation in an Indian population.

PATIENTS AND METHODS

A total of 500 patients with chronic HCV were enrolled in 19 centres across India. Genomic DNA was extracted from whole blood samples, and single nucleotide polymorphisms (SNPs) for IL28B, PNPLA3, TLR7, NOD2 and RIG-I genes were genotyped by real-time PCR using a TaqManSNP genotyping assay.

RESULTS

The mean age of the patients was 45 + 13 years, and the most common genotype observed was HCV genotype 3 (54%), followed by genotype 1 (24%). Although the allelic frequencies of TLR7, NOD2 and RIG-I were in significant disequilibrium in HCV patients compared with those in controls, the PNPLA3 polymorphism correlated significantly with higher viral load and alanine aminotransferase (ALT) levels in genotype 3 patients. Patients with PNPLA3 CG/GG genotypes, along with IL28B genotype CC, had higher levels of ALT than those with other genotypes.

CONCLUSION

These results indicate that PNPLA3 polymorphisms are associated with higher ALT levels in HCV genotype 3 patients in India and can help in identifying people who are at greater risk of developing HCV-associated liver diseases.

An assessment of toll-like receptor 7 and 8 gene polymorphisms with susceptibility to HIV-1 infection, AIDS development and response to antiretroviral therapy

Toll-like receptors (TLRs) play an important role in activating the innate immune response, inducing inflammation and initiating the adaptive immune response. In this study, we assess the influence of TLR7 and TLR8 gene polymorphisms on HIV-1 susceptibility, AIDS development, and treatment outcomes. The TLR7 and TLR8 single nucleotide polymorphisms (SNPs) were genotyped through real-time PCR in 222 patients living with HIV-1 and 141 healthy controls. Frequencies of the TLR7-IVS2-151 G/A and TLR7-IVS1 + 1817 G/T genotypes and alleles were not significantly increased in patients with HIV-1 infection compared to healthy controls both in males and females. Whereas, males carrying TLR8 Met allele were twice susceptible to HIV-1 infection compared to subjects with A allele (OR = 2.04, 95 % CI 1.10-3.76; p = 0.021). Interestingly, for TLR8-129 G/C, both males and females carrying G allele and GG genotype, respectively were significantly associated with HIV-1 infection (p < 0.0001). Moreover, the TLR7 IVS1 + 1817 G/T and the TLR8 rs3764880 were associated with protection to progress the AIDS stage in male and female, respectively (p < 0.05). Males carrying TLR7 IVS2-151-A allele showed a significant increased level of HIV-1 viral load pre-treatment, in comparison with individuals carrying the G allele (p-value = 0.036). Additionally, males carrying TLR8 Met allele showed statistically higher HIV viral load at baseline (p-value = 0.04) and after treatment (p-value = 0.013). Regarding CD4 + T cell counts, no significant association was found with TLR7 and TLR8 SNPs before and after antiretroviral treatment. This data demonstrates that TLR8 polymorphisms could affect HIV-1 infection. Moreover, an association between TLR7 IVS2-151-A and TLR8 Met alleles and plasma HIV viral load level was found.

Genetic mutations in NF-κB pathway genes were associated with the protection from hepatitis C virus infection among Chinese Han population

Host genetic polymorphism is one of major unalterable major factors for HCV infection. NF-κB proteins play multiple roles in immune response and involve in HCV infection and progression. This study was conducted to explore the relationship between single nucleotide polymorphisms (SNPs) in NF-κB pathway and the susceptibility as well as resolution of HCV infection. A total of 1642 Chinese subjects were enrolled in the study, including 963 uninfected control cases, 231 cases with spontaneous viral clearance and 448 cases with persistent HCV infection, and four SNPs (Rel rs842647, NF-κB2 rs12769316, RelA rs7101916, RelB rs28372683) were genotyped by TaqMan assay among them. Potentially functional polymorphisms were analyzed using online bioinformatics tools. The logistic analyses results indicated that RelA rs7101916 T allele (PBonferroni = 0.016) and RelB rs28372683 A allele (PBonferroni = 4.8e-5) were associated with an decreased risk of the susceptibility to HCV infection among Chinese Han population, which were consistent with the results of cumulative effects and haplotype analysis. The silico analysis of SNPs function suggested that the genetic variation of rs7101916 and rs28372683 could influence gene transcriptional regulation and expression, subsequently affecting NF-κB pathway activation and the susceptibility to HCV infection. This study firstly reported that the carriage of RelA rs7101916 T or RelB rs28372683 A was the potential protective factor against HCV infection among the Chinese population.

Genetic variations in toll-like receptors 7 and 8 modulate natural hepatitis C outcomes and liver disease progression

BACKGROUND & AIMS

The natural outcomes of hepatitis C virus (HCV) as well as the progression of the liver disease are highly variable and depend primarily on an efficient immune response. As toll-like receptors seven (TLR7) and eight (TLR8) are important effectors of the innate immunity, this study aims to evaluate the association between TLR7 and TLR8 polymorphisms and the HCV infection outcomes in Moroccan subjects.

METHODS

In this case-control study, 643 subjects including 293 mild chronic hepatitis patients, 119 with advanced liver disease (AdLD), 93 with HCV spontaneous clearance and 138 healthy controls were genotyped using TaqMan SNPs assays.

RESULTS

Patients carrying TLR7 rs179008-A allele were more likely to clear the virus spontaneously (P = .0001 for women, and P < .001 for men). Besides, carriage of TLR7 rs179009-A allele was associated with a twofold increase in spontaneous viral clearance in female patients (P = .0002), but not in men. In addition, we observed that TLR7 rs179008-T and rs179009-G alleles increased the risk of disease progression in both sexes (P < .05). TLR8 rs3764880-G allele was associated with spontaneous HCV clearance in both sexes (P < .0001) albeit with an apparently stronger association in males (OR = 6.02 for men vs 2.2 for women). In males, TLR8 rs3764879-C and TLR8 rs3764880-A alleles were significantly associated with AdLD status (P < .05).

CONCLUSIONS

Our results suggest that variations in TLR7 and TLR8 genes modulate the clearance and progression of HCV infection with different magnitudes between sexes. Our results refine, therefore, our understanding of the sex-specific differences observed regarding the susceptibility to chronic hepatitis.

Genetic variations in NF-κB were associated with the susceptibility to hepatitis C virus infection among Chinese high-risk population

Polymorphisms within NF-κB pathway genes may be linked to hepatitis C virus (HCV) infection susceptibility and outcomes. We investigated the associations between single nucleotide polymorphisms (SNPs) in NF-κB and the susceptibility as well as resolution of HCV infection. A Chinese population, including 1125 uninfected control cases, 558 cases with spontaneous viral clearance and 898 cases with persistent HCV infection, was genotyped for four SNPs (rs11820062, rs230530, rs1056890 and rs3774963) using a TaqMan assay. Our logistic analyses indicate that the subjects carrying RelA rs11820062 A allele had a significantly increased risk of HCV susceptibility (P Bonferroni  < 0.003125 in a dominant or additive model). In stratified analysis, the increased risk associated with rs11820062 A allele on HCV susceptibility remained in some case subgroups. This study demonstrates that a genetic variant involved in the NF-κB pathway gene (rs11820062 A allele) is associated with an increased HCV susceptibility within a high-risk Chinese population.

Toll like receptor7 polymorphisms in relation to disease susceptibility and progression in Chinese patients with chronic HBV infection

Toll-like receptors (TLRs) play a key role in innate and adaptive immunity, protecting the host from viral pathogens. We studied the effect of TLR7 polymorphisms on disease susceptibility and progression of chronic hepatitis B (CHB) infection in Chinese adults. Blood samples were taken from 612 patients with confirmed CHB, hepatitis B virus (HBV)-related liver cirrhosis (LC) or hepatocellular carcinoma (HCC) and 293 controls. TLR7 polymorphisms (rs179010-C > T, rs2074109-T > C, and rs179009-A > G) were analyzed by PCR-based sequencing. A significantly higher frequency of TLR7 rs179010 C allele was found in male CHB patients than in controls (74.8% vs 59.5%, P = 0.002). The frequency of rs179009 G allele was markedly increased with disease progression when male patients with CHB, LC and HCC were compared (P = 0.012). The haplotype CTA was significantly associated with an increased susceptibility to CHB among male patients (P = 0.000). Frequency of the haplotype CTG was higher in male patients with HCC than CHB (P = 0.005). No such differences in these allele frequencies were found between female patients and controls. Our results indicated that TLR7 polymorphisms play an important role in disease susceptibility and the progression of CHB infections in Chinese adults, and may partly explain the high incidence of HBV related diseases in Chinese men.

A preliminary investigation on single nucleotide polymorphism rs2287622 of bile salt export pump gene in patients with chronic hepatitis C virus infection in Hunan, China

BACKGROUND

European researchers have underscored associations between single nucleotide polymorphism (SNP) rs2287622 of the hepatobiliary bile salt export pump (BSEP) gene and the risk of hepatitis C virus (HCV) infection. The distributions of SNP rs2287622 are racially specific. This study was aimed to preliminarily investigate the distribution of BSEP gene SNP rs2287622 in the Han patients with chronic HCV-infection (CHC) in Hunan, China.

METHODS

BSEP gene SNP rs2287622 of 165 CHC patients, 99 patients with chronic hepatitis B virus infection (CHB) and 99 healthy individuals were analyzed by polymerase chain reaction-restriction fragment length polymorphism analysis and nucleotide sequencing.

RESULTS

The overall frequencies of the C allele of BESP gene SNP rs2287622 in the CHC patients, CHB patients and healthy individuals were 74.2, 72.7 and 74.2%, respectively (P > 0.05). The overall odds ratios (ORs) aiming at predicting CHC risk by comparing the ratios of the frequency distribution of alleles or genotypes in the CHC group with those in the non-CHC group had no statistical significance (P > 0.05). However, the CHC ORs of CC vs TT, TC vs TT and CC + CT vs TT among the individuals aged over 40 years were 2.680, 3.122 and 2.824 respectively (P < 0.05), and the higher risk did not relate to gender, HCV genotypes and presence of HCV-related liver cirrhosis.

CONCLUSIONS

Among the Han individuals aged over 40 years in Hunan, China, genotype CC or CT of BSEP gene SNP rs2287622 may correlate with higher risk of CHC in comparison with genotype TT. Further study with a larger cohort is essential.

Genetic variations in vitamin D receptor were associated with the outcomes of hepatitis C virus infection among Chinese population

Vitamin D has been considered as an immune modulator, and exerted the effect through the vitamin D receptor (VDR). This study investigated the associations of single-nucleotide polymorphisms (SNPs) of VDR with the outcomes of Hepatitis C virus (HCV) infection. Three SNPs (rs2228570, rs757343 and rs739837) were genotyped by TaqMan assay among Chinese population, including 538 HCV spontaneous clearance subjects, 834 persistent infection subjects and 1030 uninfected subjects. Binary logistic analyses were used to control the effects of confounding factors. The results showed that subjects with the rs757343 A allele and rs739837 A allele had the significantly reduced risk of HCV susceptibility (all PBonferroni<0.05 in dominant/additive model). In the stratified analysis, the protection of rs757343 A allele and rs739837 A allele against HCV infection remained effective in some subgroups. In addition, patients carrying rs739837 CA genotype were less prone to develop persistent infection (PBonferroni=0.033) and such effect still work in several subgroups in the stratified analysis. Furthermore, haplotype analysis indicated that when compared with the most frequent GC haplotype, the haplotype carrying AA (odds ratio (OR)=0.66, 95% confidence interval (CI)=0.56-0.78) and GA (OR=0.64, 95% CI=0.47-0.85) suggested a protective effect. Our findings indicated that the polymorphisms of VDR are associated with the outcomes of HCV infection among Chinese population.

Effects of Virus-associated Molecular Patterns on the Expression of Cathelicidins in the Hen Vagina

The aim of this study was to examine the expression profiles of the cathelicidins (CATHs) in the oviduct and the effects of Toll-like receptor (TLR) ligands of virus-associated molecular patterns on CATHs expression in the vagina of hens. The mRNA expression of cathelicidins (CATH1, -2, -3 and -B1) in the oviductal mucosa was analyzed by RT-PCR. The effects of viral moleculs on the CATHs expression in the vagina was examined by incubating the mucosal tissue with virus molecular patterns, including poly I:C (dsRNA virus, TLR3 ligand), R848 (ssRNA virus, TLR7 ligand) and CpG-ODN (DNA virus, TLR21 ligand), followed by real-time PCR analysis. The expression of CATH1, CATH2 and CATH3 was identified in all oviductal segments, except for CATH2 which was lacked in the magnum. The expression of CATHB1 was not identified at any segments of the oviduct. Poly I:C down-regulated the expression of CATH1, -2 and -3, whereas R848 up-regulated the expression of CATH1 and CATH3 but down-regulated the expression of CATH2. CpG-ODN did not affect the CATHs expression. These results suggest that mucosal tissues of the oviduct express CATHs to provide the defense mechanism against microbes, and the expression of CATH1 and CATH3 is up-regulated against ssRNA viruses, whereas, dsRNA virus may suppress the expression of CATH1, -2 and -3.

Interferon-λ-related genes and therapeutic response in Chinese hepatitis C patients

AIM

To determine the association between rapid viral response and IL28B, IL28RA, IL10RB and MxA polymorphisms in the Chinese Han population.

METHODS

The study cohort consisted of 238 chronic hepatitis C patients treated with interferon (IFN)-α-2b and ribavirin. Six single nucleotide polymorphisms were genotyped using the ABI TaqMan allelic discrimination assay. Biochemical indices were measured at baseline. Serum hepatitis C virus (HCV) RNA was detected at weeks 0, 4, 12 and 24 of therapy.

RESULTS

Only IL28B rs12980275 was associated with treatment response in the Chinese Han population. Patients carrying AG/GG genotypes had a reduced rapid viral response compared with patients carrying the AA genotype (additive model: adjusted OR = 0.43, 95%CI: 0.24-0.75). It took less time for patients with the AA genotype to achieve a viral load < 500 copies/mL (log-rank test, P = 0.004). In addition, the protective effect of genotype AA was independent of baseline viral load. HCV genotype, and baseline white blood cell count, α-fetoprotein and viral load might also help predict treatment response. The area under the receiver-operating characteristic curve was 0.726.

CONCLUSION

IL28B rs12980275 AA genotype is a strong predictor of positive response to IFN therapy in Chinese Han patients with hepatitis C.

Effects of different TLR ligands on the expression of proinflammatory cytokines and avian β-defensins in the uterine and vaginal tissues of laying hens

The immune response in the lower part of the hen oviduct is of crucial importance to protect the oviductal tissues from infection by microorganisms colonizing the cloaca. The aim of this study was to examine whether different TLRs can recognize their ligands to induce expression of proinflammatory cytokines and avian β-defensins (AvBDs) in the uterus and vagina of laying hens. The mucosal tissues of the uterus and vagina were collected, cultured in TCM-199 medium and stimulated with or without different ligands of TLRs, namely Pam3CSK4 (TLR2), poly I:C (TLR3), flagellin (TLR5), R848 (TLR7), and CpG-ODN (TLR21) and incubated for 3h. The expression of IL1B in the uterus and vagina was upregulated by all TLR ligands tested. The expression of IL6 in the uterus and vagina was upregulated by poly I:C and CpG-ODN, and it was also upregulated by Pam3CSK4 in the uterus and by R848 in the vagina. The expression of AvBD10 was upregulated by poly I:C in the uterus and by flagellin in the vagina. On the other hand, the AvBD10 expression was downregulated by CpG-ODN in the uterus and by R848 in the vagina, whereas its expression was not affected by Pam3CSK4 in both tissues. The expression of AvBD12 in the uterus and vagina was not affected by any TLR ligands except for CpG-ODN, which downregulated its expression in the vagina. These results suggest that TLR2, 3, 5, 7, and 21 in the uterine and vaginal tissues are functionally active in inducing proinflammatory cytokines in response to their specific ligands, although the effect on the expression of AvBDs is limited. Proinflammatory cytokines induced by interaction of TLRs with their ligands may play roles in the defense against infectious microorganisms.