Lack of association of TLR4 polymorphisms with susceptibility to rheumatoid arthritis and ankylosing spondylitis: a meta-analysis

Associations of toll-like receptor 4 and 2 gene polymorphisms with susceptibility to ankylosing spondylitis: A meta-analysis

BACKGROUND

The published evidences on the correlations of toll-like receptor 4 (TLR4) and TLR9 gene polymorphisms and ankylosing spondylitis (AS) were conflicting. The purpose of this study was to investigate whether TLR4 and TLR9 gene polymorphisms conferred susceptibility to AS through a meta-analysis approach.

METHODS

Databases of PubMed, Web of Science, EMBASE, Cochrane Library, CNKI and Wanfang were retrieved for relevant publications up to 20 June 2020. Study quality was assessed based on Newcastle-Ottawa scale (NOS). Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to judge the associations.

RESULTS

Totally, 13 articles with 3,055 AS cases and 4,238 controls were incorporated into this meta-analysis, and four most widely reported polymorphisms (TLR4-rs4986790, TLR4-rs4986791, TLR9-rs55704465 and TLR9-rs187084) were analysed. All included studies were in high quality. The pooled data did not support any significant association between the four studied polymorphisms and AS susceptibility.

CONCLUSIONS

The present meta-analysis suggests there is no significant association between TLR4-rs4986790, TLR4-rs4986791, TLR9-rs55704465 and TLR9-rs187084 polymorphisms and AS.

TLR4 rs41426344 increases susceptibility of rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) in a central south Chinese Han population

BACKGROUND

The aim of the study was to determine whether polymorphisms in toll-like receptor 4 (TLR4) confer susceptibility to rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) in a central south Chinese Han population.

METHODS

Genotyping for six well studied polymorphisms (rs4986790, rs4986791, rs10759932, rs41426344, rs11536889 and rs7873784) in TLR4 gene were conducted in 1074 unrelated patients with RA and 1692 healthy control subjects, as well as in 217 unrelated patients with JIA and 378 healthy control subjects using direct sequencing technique. Comparisons between cases and controls in alleles, genotypes and haplotypes were carried out using Fisher's exact test.

RESULTS

Significant genetic associations were detected between the 3'UTR rs41426344C and RA (p < 0.001, p _adj < 0.001, OR = 2.24) and JIA (p < 0.001, p _adj < 0.001, OR = 2.05). In addition, rs4986790G was found to be significantly associated with the susceptibility for RA (p = 0.005, p _adj = 0.03, OR = 3.43), but not for JIA (p = 0.06, p _adj = 0.36, OR = 2.65). Furthermore, significant increasing in the distributions of haplotypes H4 and H10 in RA (H4: p = 0.001, OR = 1.13; H10: p = 0.001, OR = 1.15) and JIA (H4: p = 0.04, OR = 2.06; H10: p = 0.02, OR = 2.47) were also found. Moreover, the frequency of rs41426344C significantly increased in RF-positive and anti-CCP positive subjects both in RA (RF⁺: p <0.0001, OR = 2.33; anti-CCP⁺: p =0.008, OR = 2.79) and JIA (RF⁺: p =0.02, OR = 2.91; anti-CCP⁺: p = 0.02, OR = 2.78).

CONCLUSIONS

Our study suggested that rs41426344 and rs4986790 of TLR4 might contribute to RA, and rs41426344 might contribute to JIA pathogenesis in central south Chinese Han population.

Relationship between the IL12B (rs3212227) gene polymorphism and susceptibility to multiple autoimmune diseases: A meta-analysis

OBJECTIVES

The purpose of this study was to evaluate whether a single-nucleotide polymorphism (SNP) IL12B 3(')UTR +1188A/C (rs3212227) confers susceptibility to several autoimmune diseases.

METHODS

A systematic literature search was conducted to identify relevant studies. Pooled odds ratio (OR) with 95% confidence interval (CI) was used to estimate the strength of association.

RESULTS

Twenty-five studies were included in the meta-analysis, which contained 9794 cases and 11,330 controls. Our result indicated that IL12B +1188A/C (rs3212227) polymorphism was associated with type-1 diabetes (T1D) in the dominant model (p = 0.008), and an increased risk was found in East Asians in the dominant model (p < 0.001). East Asians rheumatoid arthritis (RA) patients seemed to be at risk of allelic model (p = 0.011). As to Behcet's disease (BD), there was a risk in dominant model (p = 0.020) and positive associations of dominant model, allelic model in East Asians (p = 0.009; p < 0.001, respectively). But we failed to find any association between IL12B +1188A/C (rs3212227) polymorphism with Graves' disease (GD) and ankylosing spondylitis (AS).

CONCLUSIONS

The present study suggests that the IL12B +1188A/C (rs3212227) polymorphism might be associated with genetic susceptibility to autoimmune diseases, such as T1D, RA, BD, but not GD and AS.

The role of toll like receptors in giant cell arteritis

GCA is a common primary systemic vasculitis that results in granulomatous inflammation of medium to large arteries. Both innate and adaptive immune mechanisms combine to drive intimal hyperplasia, luminal stenosis and ultimately occlusion. While the pathogenesis of GCA is incompletely understood, the activation of resident adventitial dendritic cells via toll like receptors (TLRs) appears to be a crucial inciting event. Here we explore the role of TLRs in the pathogenesis of GCA, including their effects on dendritic cell and T cell activation and recruitment, putative infectious triggers for GCA and the potential of TLR inhibition as a novel therapeutic strategy in GCA.

TLR2 and TLR4 in autoimmune diseases: a comprehensive review

Autoimmune diseases are immune disorders characterized by T cell hyperactivity and B cell overstimulation leading to overproduction of autoantibodies. Although the pathogenesis of various autoimmune diseases remains to be elucidated, environmental factors have been thought to contribute to the initiation and maintenance of auto-respond inflammation. Toll-like receptors (TLRs) are pattern recognition receptors belonging to innate immunity that recognize and defend invading microorganisms. Besides these exogenous pathogen-associated molecular patterns, TLRs can also bind with damage-associated molecular patterns produced under strike or by tissue damage or cells apoptosis. It is believed that TLRs build a bridge between innate immunity and autoimmunity. There are five adaptors to TLRs including MyD88, TRIF, TIRAP/MAL, TRAM, and SARM. Upon activation, TLRs recruit specific adaptors to initiate the downstream signaling pathways leading to the production of inflammatory cytokines and chemokines. Under certain circumstances, ligation of TLRs drives to aberrant activation and unrestricted inflammatory responses, thereby contributing to the perpetuation of inflammation in autoimmune diseases. In the past, most studies focused on the intracellular TLRs, such as TLR3, TLR7, and TLR9, but recent studies reveal that cell surface TLRs, especially TLR2 and TLR4, also play an essential role in the development of autoimmune diseases and afford multiple therapeutic targets. In this review, we summarized the biological characteristics, signaling mechanisms of TLR2/4, the negative regulators of TLR2/4 pathway, and the pivotal function of TLR2/4 in the pathogenesis of autoimmune diseases including rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, Sjogren's syndrome, psoriasis, multiple sclerosis, and autoimmune diabetes.

Association of Toll like receptor Asp299Gly with rheumatoid arthritis risk: a systematic review of case-control studies and meta-analysis

OBJECTIVE

Rheumatoid arthritis (RA) is thought to be triggered by various genetic and environmental factors. Few human epidemiologic studies demonstrated that single nucleotide polymorphisms (SNPs) in Toll-like receptor (TLR) genes are associated with RA. We aimed to evaluate the effects of TLR polymorphisms on the risk of RA pathogenesis by using a meta-analysis approach.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, a systematic search and meta-analysis of the literature was conducted. We screened the medical literature based on keywords search in MEDLINE and EMBASE 'Toll-like receptor', 'polymorphism', and rheumatoid arthritis. Meta-analyses were performed under the random-effects model by using: (1) recessive, (2) homozygous, (3) dominant, (4) codominant and allele contrast models.

RESULTS

A total of 3086 cases and 3756 controls in nine studies were included in the meta-analysis. Association between TLR4 Asp299Gly and RA risk was marginally significant [OR = 0.856 (95% CI, 0.716-1.022); P = 0.086] in the homozygous model. AA and GG homozygote genotypes tended to be significant protective factors against RA risk.

CONCLUSION

Our overall analyses indicated that TLR4 Asp299Gly polymorphism might contribute to RA pathogenesis.

MicroRNA-323-3p with clinical potential in rheumatoid arthritis, Alzheimer's disease and ectopic pregnancy

INTRODUCTION

MicroRNAs (miRNAs) are a group of noncoding RNAs,∼ 20 - 22 nucleotides in length, that repress target gene expression through mRNA degradation and translation inhibition. The gene encoding miR-323-3p, which is a biomarker in immune and inflammatory responses, exists in a miRNA cluster in chromosomal region 14q32.31. It has been shown that miR-323-3p associates with the pathogenesis of several diseases, such as rheumatoid arthritis, Alzheimer's disease and ectopic pregnancy.

AREAS COVERED

This review provides a current view on the association of miR-323-3p with several human diseases and is focused on the recent studies of miR-323-3p regulation, discussing its potential as an epigenetic biomarker and therapeutic target for these diseases. In particular, the mechanisms of miR-323-3p in these diseases and how miR-323-3p is regulated are also discussed.

EXPERT OPINION

Although the exact role of miR-323-3p in these diseases has not been fully elucidated, targeting miR-323-3p may serve as a promising therapy strategy.

IL-33 in rheumatoid arthritis: potential role in pathogenesis and therapy

Rheumatoid arthritis (RA) is characterized by chronic inflammatory disease, including synovial proliferation and excessive pro-inflammatory cytokines production, leading to cartilage and bone destruction. Cytokine-mediated immunity plays an important role in the pathogenesis of various autoimmune diseases such as RA. Recently, the IL-1 family member IL-33, was recognized to perform as an inflammatory cytokine, exerted profound effects in human RA and experimental inflammatory arthritis. Furthermore, inhibition of IL-33 signaling proposed a potential therapeutic approach. In this review, we summarize recent advances on the pathological roles of IL-33 in RA and discuss the therapeutic significance of these new findings.

IL-32 with potential insights into rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease, characterized by chronic inflammation in synovial joints. Effective treatment for RA is lacking because the clear etiology and pathogenesis of RA have not been fully elucidated. Cytokine-mediated immunity has been found to play an important role in the pathogenesis of various autoimmune diseases such as RA. Recently, IL-32 is identified with high expression in RA patients and mice models of experimental inflammatory arthritis. IL-32 is recognized to play a crucial role in RA with pro-inflammatory effects. Furthermore, interventions for blocking IL-32 in RA seem possible and applicable. Therefore, targeting IL-32 may give therapeutic potential. In this article, we discuss the biological features of IL-32 and summarize recent advances in understanding the role of IL-32 in disease onset of and treatment for RA. Hopefully the information obtained will benefit for developing novel therapeutic strategies.