A single-nucleotide polymorphism in TLR4 is linked with the risk of HIV-1 infection

M2a macrophages facilitate resolution of chemically-induced colitis in TLR4-SNP mice

IMPORTANCE

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, impacts millions of individuals worldwide and severely impairs the quality of life for patients. Dysregulation of innate immune signaling pathways reduces barrier function and exacerbates disease progression. Macrophage (Mφ) signaling pathways are potential targets for IBD therapies. While multiple treatments are available for IBD, (i) not all patients respond, (ii) responses may diminish over time, and (iii) treatments often have undesirable side effects. Genetic studies have shown that the inheritance of two co-segregating SNPs expressed in the innate immune receptor, TLR4, is associated with human IBD. Mice expressing homologous SNPs ("TLR4-SNP" mice) exhibited more severe colitis than WT mice in a DSS-induced colonic inflammation/repair model. We identified a critical role for M2a "tissue repair" Mφ in the resolution of colitis. Our findings provide insight into potential development of novel therapies targeting Mφ signaling pathways that aim to alleviate the debilitating symptoms experienced by individuals with IBD.

Role of TLRs in HIV-1 Infection and Potential of TLR Agonists in HIV-1 Vaccine Development and Treatment Strategies

Toll-like receptors (TLRs), as a family of pattern recognition receptors, play an important role in the recognition of HIV-1 molecular structures by various cells of the innate immune system, but also provide a functional association with subsequent mechanisms of adaptive immunity. TLR7 and TLR8 play a particularly important role in the innate immune response to RNA viruses due to their ability to recognise GU-rich single-stranded RNA molecules and subsequently activate intracellular signalling pathways resulting in expression of genes coding for various biological response modifiers (interferons, proinflammatory cytokines, chemokines). The aim of this review is to summarise the most recent knowledge on the role of TLRs in the innate immune response to HIV-1 and the role of TLR gene polymorphisms in the biology and in the clinical aspects of HIV infections. In addition, the role of TLR agonists as latency reversing agents in research to treat HIV infections and as immunomodulators in HIV vaccine research will be discussed.

The relationship between 896A/G (rs4986790) polymorphism of TLR4 and infectious diseases: A meta-analysis

Toll-like Receptors (TLRs), such as the TLR4, are genes encoding transmembrane receptors of the same name, which induce a pro- or anti-inflammatory response according to their expression as the host's first line of defense against pathogens, such as infectious ones. Single nucleotide polymorphisms (SNPs) are the most common type of mutation in the human genome and can generate functional modification in genes. The aim of this article is to review in which infectious diseases there is an association of susceptibility or protection by the TLR4 SNP rs4986790. A systematic review and meta-analysis of the literature was conducted in the Science Direct, PUBMED, MEDLINE, and SciELO databases between 2011 and 2021 based on the dominant genotypic model of this SNP for general and subgroup analysis of infectious agent type in random effect. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated for genotypic comparison. I² statistics were calculated to assess the presence of heterogeneity between studies and funnel plots were inspected for indication of publication bias. A total of 27 articles were included, all in English. Among the results achieved, the categories of diseases that were most associated with the SNP studied were in decreasing order of number of articles: infections by bacteria (29.63%); caused by viruses (22.23%); urinary tract infection-UTI (7.4%), while 11 studies (40.74%) demonstrated a nonsignificant association. In this meta-analysis, a total of 5599 cases and 5871 controls were finalized. The present meta-analysis suggests that there is no significant association between TLR4-rs4986790 SNP and infections (OR = 1,11; 95% CI: 0,75-1,66; p = 0,59), but in the virus subgroup it was associated with a higher risk (OR = 2,16; 95% CI: 1,09-4,30; p = 0,03). The subgroups of bacteria and parasites did not show statistical significance (OR = 0,86; 95% CI: 0,56-1,30; p = 0,47, and no estimate of effects, respectively). Therefore, it has been shown that a diversity of infectious diseases is related to this polymorphism, either by susceptibility or even severity to them, and the receptor generated is also crucial for the generation of cell signaling pathways and immune response against pathogens.

Single nucleotide polymorphisms of whole genes and atrophic gastritis susceptibility:a systematic review and meta-analysis

BACKGROUND

Atrophic gastritis (AG) is one of the important precancerous lesions of gastric cancer. Single nucleotide polymorphisms (SNPs) are closely related to AG susceptibility. However, the research conclusions on the predictive potential of SNPs are inconsistent. The study aims to retrospect the association between SNPs of whole genes and AG risk by meta-analysis.

MATERIALS AND METHODS

Up to April 29, 2020, a systematic literature search for the relationship of SNPs with AG susceptibility was performed utilizing PubMed, Web of Science and Chinese National Knowledge Infrastructure. The overall and stratified meta-analyses on extracted data were conducted by Stata11.2.

RESULTS

33 case-control studies were enrolled containing 9951 AG patients and 17,252 healthy controls, and 17 SNPs in 12 different genes were systematically reviewed. The results indicated that 12 genes could be categorized based on their functions, including immune response, cell proliferation and apoptosis, and DNA damage repair. For the SNPs in immune response-related genes, the C allele of TLR1 rs4833095 T/C increased AG risk to 1.21-fold and the recessive model of TLR4 rs11536878 in the TLR gene family decreased AG susceptibility to 0.48-fold. The variant alleles of IL-10 rs1800871 (OR = 1.21) and IL-8 rs4073 (OR = 1.22) in the IL gene family were positively associated with AG risk. PSCA rs2294008 enhanced AG risk in all genetic models. SNPs associated with AG susceptibility were mainly focused on immune response-related genes.

CONCLUSION

These SNPs related to immune response could influence on AG risk and have potential to be AG predictive biomarkers. It is worth noting that the number of studies for each SNPs were insufficient due to the limited published researches and updated meta-analysis needs to be performed based on extensive relevant studies for more reliable results.

Strong Association of the rs4986790 Single Nucleotide Polymorphism (SNP) of the Toll-Like Receptor 4 (TLR4) Gene with Human Immunodeficiency Virus (HIV) Infection: A Meta-Analysis

Human immunodeficiency virus (HIV) causes acquired immune deficiency syndrome (AIDS) and enters the host cell via CD4 and either CC-chemokine receptor 5 (CCR) or CXC-chemokine receptor 4 (CXCR4). HIV is directly recognized by toll-like receptor 4 (TLR4) and affects downstream immune-related signal pathways. In addition, stimulated TLR4 inhibits HIV-1 invasion, and the rs4986790 single nucleotide polymorphism (SNP) (D299G) of the TLR4 gene contributes to the risk of HIV-1 infection in an Indian population. To evaluate whether the rs4986790 SNP of the TLR4 gene is related to vulnerability to HIV-1 infection, we collected genetic information from HIV-1 patients in previous studies and performed an association analysis with a matched control population obtained from the 1000 Genomes Project. In addition, to strengthen the results of association analysis, we performed a meta-analysis. We identified a strong association between the rs4986791 SNP and susceptibility to HIV infection in HIV-infected patients in previous studies and a matched control population obtained from the 1000 Genomes Project. In addition, we found that the G allele of the rs4986791 SNP in the TLR4 gene is strongly related to susceptibility to HIV infection in three Caucasian populations (odd ratio = 2.29, 95% confidence interval: 1.72–3.07, p = 1.438 × 10⁻⁷) and all four populations (odd ratio = 2.22, 95% confidence interval: 1.74–2.84, p = 2 × 10⁻¹⁰) in a meta-analysis. To the best our knowledge, this was the first meta-analysis on the association between the rs4986791 SNP of the TLR4 gene and susceptibility to HIV infection.

Association of toll-like receptor polymorphisms with acquisition of HIV infection and clinical findings: A protocol for systematic review and meta-analysis

BACKGROUND

To find the relationship between toll-like receptor (TLR) gene variants and human immunodeficiency virus (HIV) infection and clinical findings, which could inform clinical decisions and vaccination strategies.

METHOD

Four databases were searched for articles that were published on or before Jul.1, 2020. Review Manager 5.3 software was applied to perform meta-analysis to explore.

RESULTS

A total of 10 studies involving 20 genes, 3697 cases, and 6498 controls were included in this systematic review. TLR2 -196 to -174 Ins/Del (odds ratio [OR] = 1.562; P = .002), TLR4 rs4986790 (OR = 2.05; P = .002), TLR3 rs3775291 (OR = 0.25; P = .03), TLR7 rs179008 (P = .002), TLR7 rs2074109 (OR = 0.27, P = .019) were found associated with HIV infection. TLR2 -196 to -174, TLR4 rs4986790, TLR7 rs179008, TLR8 rs3764880, TLR9 rs352140 were found associated with clinical findings of HIV infection. We identified 5 case-control studies in meta-analysis, involving 695 cases and 729 controls on TLR7 rs179008 polymorphism, totaling 652 cases and 614 controls on TLR9 rs352140 polymorphism. In meta-analysis, we employed various genetic models. The T allele of TLR7 rs179008 was conferred the risk of HIV infection (T vs A: OR = 1.25, PA = .02). An increased risk of HIV infection was found for individuals with the TLR9 rs352140 GG genotype (GG vs AA: OR = 1.50, PA = .04).

CONCLUSIONS

The systematic review indicated that TLR7 rs179008 T allele provides risk effects for HIV infection. TLR9 rs352140 GG genotype may associate with HIV infection.

The Role of Toll-Like Receptors in Retroviral Infection

Toll-like receptors (TLRs) are key pathogen sensing receptors that respond to diverse microbial ligands, and trigger both innate and adaptive immune responses to infection. Since their discovery, a growing body of evidence has pointed to an important role for TLRs in retroviral infection and pathogenesis. These data suggest that multiple TLRs contribute to the anti-retroviral response, and that TLR engagement by retroviruses can have complex and divergent outcomes for infection. Despite this progress, numerous questions remain about the role of TLRs in retroviral infection. In this review, I summarize existing evidence for TLR-retrovirus interactions and the functional roles these receptors play in immunity and pathogenesis, with particular focus on human immunodeficiency virus (HIV).

TLR4 896A/G and TLR9 1174G/A polymorphisms are associated with the risk of infectious mononucleosis

Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns and activate innate and adaptive immune responses. Single nucleotide polymorphisms (SNPs) within the TLR genes may influence host–pathogen interactions and can have an impact on the progression of infectious diseases. The present study aimed to investigate the genotype distribution of TLR2 (2029C/T, rs121917864; 2258G/A, rs5743708), TLR4 (896A/G, rs4986790), and TLR9 (− 1237T/C, rs5743836; − 1486T/C, rs187084; 1174G/A, rs352139; and 2848C/T, rs352140) polymorphisms in 149 children and adolescents with infectious mononucleosis (IM) and 140 healthy individuals. The potential association of TLR SNPs with the clinical manifestations of EBV infection was also studied. The presence of TLR2, TLR4, and TLR9 SNPs was identified by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP). EBV DNA loads were detected by quantitative real-time PCR assay. The TLR4 896 GG and the TLR9 1174 GA genotypes were associated with an increased risk of EBV-related IM in examined patients (p = 0.014 and p = 0.001, respectively). The heterozygous genotype of the TLR4 896A/G SNP was associated with an increased risk of elevated liver enzyme levels and leukocytosis (p < 0.05). Our preliminary study revealed that the TLR4 896A/G and the TLR9 1174G/A polymorphisms seem to be related to the course of acute EBV infection in children and adolescents.

British Journal of Biomedical Science in 2019. What have we learned?

In 2019 the British Journal of Biomedical Science published 40 articles in the various disciplines that comprise biomedical science. These were one review, 22 original articles and 17 'In Brief' short reports. Of those citing original data, the majority were in cellular pathology (14 papers), clinical chemistry (9 papers), and microbiology (6 papers: 4 in bacteriology and 2 in virology). There were 3 papers in haematology and 2 in andrology, whilst 5 papers crossed traditional discipline boundaries (such as the molecular genetics of IL6, liver function tests, and hepatocellular carcinoma). Over two-thirds of papers used techniques in molecular genetics. The present report will summarise key aspects of these publications that are of greatest relevance to laboratory scientists.