Association between toll-like receptor 10 (TLR10) gene polymorphisms and childhood IgA nephropathy

Analysis of TLR10 gene polymorphisms in patients with rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic systemic disease characterized by inflammatory synovitis, and genetic factors play the greatest role in RA. This study aimed to investigate the relationship between Toll-like receptor 10(TLR10) gene polymorphisms and susceptibility to RA.

METHODS

A total of 271 patients with RA and an equal number of healthy controls were included, and the TLR10 rs2101521, rs10004195 and rs11725309 loci were genotyped by time-of-flight mass spectrometry.

RESULTS

Compared with healthy controls, Individuals carrying the rs2101521 G allele had an increased risk of developing RA (P = 0.01; odds ratio (OR) = 1.367; 95 % confidence interval (CI): 1.076-1.736). Individuals with the rs2101521 GG genotype had a greater risk of RA (P = 0.01; OR = 1.816; 95 % CI: 1.161-2.984). Stratified analysis demonstrated a greater prevalence of positive anti-cyclic citrullinated peptide (CCP)antibody in patients carrying the rs2101521 G allele (P = 0.03). Additionally, patients with the rs11725309 CT genotype had elevated levels of C-reactive protein (CRP)(P = 0.007).

CONCLUSION

In conclusion, TLR10 gene polymorphisms are associated with RA susceptibility.

TLR10 (CD290) Is a Regulator of Immune Responses in Human Plasmacytoid Dendritic Cells

TLRs are the most thoroughly studied group of pattern-recognition receptors that play a central role in innate immunity. Among them, TLR10 (CD290) remains the only TLR family member without a known ligand and clearly defined functions. One major impediment to studying TLR10 is its absence in mice. A recent study on TLR10 knock-in mice demonstrated its intrinsic inhibitory role in B cells, indicating that TLR10 is a potential drug target in autoimmune diseases. In this study, we interrogated the expression and function of TLR10 in human plasmacytoid dendritic cells (pDCs). We have seen that primary human pDCs, B cells, and monocytes constitutively express TLR10. Upon preincubation with an anti-TLR10 Ab, production of cytokines in pDCs was downregulated in response to stimulation with DNA and RNA viruses. Upon further investigation into the possible mechanism, we documented phosphorylation of STAT3 upon Ab-mediated engagement of TLR10. This leads to the induction of inhibitory molecule suppressor of cytokine signaling 3 (SOCS3) expression. We have also documented the inhibition of nuclear translocation of transcription factor IFN regulatory factor 7 (IRF7) in pDCs following TLR10 engagement. Our data provide the (to our knowledge) first evidence that TLR10 is constitutively expressed on the surface of human pDCs and works as a regulator of their innate response. Our findings indicate the potential of harnessing the function of pDCs by Ab-mediated targeting of TLR10 that may open a new therapeutic avenue for autoimmune disorders.

IgA Nephropathy: Emerging Mechanisms of Disease

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis reported across the world and is characterized by immunoglobulin A (IgA) dominant mesangial deposits, which are poorly O-glycosylated. This deposition leads to a cascade of glomerular and tubulointerstitial inflammation and fibrosis, which can progress to chronic kidney disease. The variability in rate of progression reflects the many genetic and environmental factors that drive IgAN. Here, we summarize the contemporary understanding of the disease mechanisms that drive IgAN and provide an overview of new and emerging therapies, which target these mechanisms.

TLR10 genotypes affect long-term graft function in tacrolimus-treated solid organ transplant recipients

The present study was conducted to investigate the relationship between single nucleotide polymorphisms (SNPs) in TLR10 and the clinical outcomes of renal transplant patients who took tacrolimus (TAC) as an immunosuppressant, and further confirmed the results in liver transplant patients. A total of 172 renal transplant patients and 145 pairs of liver transplant recipients and donors were included. Nineteen SNPs of TLR10 gene were detected by matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS). The associations of recipient SNPs with TAC-related clinical outcomes were explored in renal transplant recipients. The relationship between recipient and donor SNPs and the clinical outcomes of liver transplant patients were investigated to confirm the results. Three SNPs (rs28393318, rs11466655 and rs11096957) in renal transplant recipients were found to influence the graft function after transplantation (P = 0.00003, 0.001 and 0.000003, respectively). The recipient rs11096957 was also found to affect the TBil, and DBil levels in liver transplant recipients (P = 0.001 and 0.002). In this study, we identified significant association signals from TLR10 polymorphisms with clinical outcomes in TAC-treated transplant patients in a Chinese Han-based sample. We provide some evidence for the effect between rs11096957 in TLR10 gene on the graft functions in both renal and liver transplantation.

TLR10 and Its Role in Immunity

Toll like receptors (TLRs) are the most studied pattern recognition receptors (PRRs) as they connect the innate to the acquired immune response. To date, there are ten human TLRs which are expressed either on the plasma membrane or on the endosomes. TLR1, TLR2, TLR4, TLR5, TLR6 and TLR10 are plasma membrane TLRs that recognise extracellular components of pathogens, whereas TLR3, TLR7, TLR8 and TLR9 are located on endosomes where they recognise foreign nucleic acids. Of these TLRs, TLR10 is the latest human TLR to be discovered and its function and ligands are still unclear. TLR10 is the only known member of TLR family that can elicit anti-inflammatory effect. TLR10 can inhibit other TLRs by competing with stimulatory TLRs, dimerising with TLR1, TLR2 and TLR6, and by inducing PI3K/Akt to produce IL-1Ra. There is controversy on the function of TLR10 as an anti-inflammatory TLR as initial studies on TLR10 revealed it to promote inflammation. Herein, we review the detailed functions of TLR10 in immunity and give an account of how and when TLR10 can act on both sides of the inflammatory spectrum.

TLR10 and Its Unique Anti-Inflammatory Properties and Potential Use as a Target in Therapeutics

TLRs are pattern recognition receptors (PRRs) whose cytoplasmic signalling domain is similar to that of IL-1. The extracellular domain of TLRs serve as the binding site of pathogen associated molecular patterns. TLRs are found on both plasma and endosomal membranes and they mainly exert their function by activating genes which lead to production of inflammatory factors. The latest TLR to be discovered, TLR10 is a unique TLR which exhibit anti-inflammatory properties. TLR10 is found on the plasma membrane with other TLRs namely TLR1, TLR2, TLR4, TLR5 and TLR6. Studies have revealed that TLR10 is found on the same gene cluster with TLR1 and TLR6 and is also a coreceptor of TLR2. Up to date, TLR10 is the only TLR which exhibit anti-inflammatory property. Previously, TLR10 was thought to be an “orphan receptor” but much recent studies have identified ligands for TLR10. Currently there is no review article on TLR10 that has been published. In this narrative review, we are going to give an account of TLR10, its functions mainly as an anti-inflammatory PRR and its possible applications as a target in therapeutics.

Association of toll-like receptor 10 polymorphisms with paediatric idiopathic uveitis in Han Chinese

AIMS

We aimed to determine whether paediatric idiopathic uveitis (PIU) and juvenile idiopathic arthritis associated paediatric uveitis (JIA-PU) have an association with Toll-like receptor 10 (TLR10) gene polymorphisms in Han Chinese.

METHODS

Ten tag single nucleotide polymorphisms (SNPs) of TLR10 were analysed in 992 PIU patients, 127 JIA-PU patients and 1600 controls using the Sequenom MassARRAY system and iPLEX Gold assay. Genotype and allele frequencies were analysed using the χ2 test. A stratified analysis was performed according to the clinical features of PIU.

RESULTS

Increased frequencies of the rs2101521 A allele, rs10004195 A allele, rs11725309 CC genotype and rs6841698 AA genotype were found in PIU patients compared with controls (corrected p values (Pc)=1.81×10^-4, Pc= 1.12×10^-2, Pc=2.41×10^-2 and Pc=3.29×10^-3, respectively). There was no association between these 10 tag SNPs and JIA-PU. In the stratified analysis, the frequency of the rs6841698 A allele was higher in PIU patients with cataract (Pc=1.45×10^-6). The frequencies of the rs2101521 A allele and rs6841698 AA genotype were increased in PIU patients with band keratopathy (BK) (Pc=2.32×10^-2, Pc=3.30×10^-3, respectively).

CONCLUSION

TLR10 gene polymorphisms (rs2101521, rs10004195, rs11725309 and rs6841698) confer susceptibility to PIU in Han Chinese. In a stratified analysis, rs2101521 and rs6841698 are associated with PIU with BK, and rs6841698 correlates with PIU with cataract.

New insights into the pathogenesis of IgA nephropathy

IgA nephropathy is the most common form of glomerulonephritis in many parts of the world and remains an important cause of end-stage renal disease. Current evidence suggests that IgA nephropathy is not due to a single pathogenic insult, but rather the result of multiple sequential pathogenic "hits". An abnormally increased level of circulating poorly O-galactosylated IgA1 and the production of O-glycan-specific antibodies leads to the formation of IgA1-containing immune complexes, and their subsequent mesangial deposition results in inflammation and glomerular injury. While this general framework has formed the foundation of our current understanding of the pathogenesis of IgA nephropathy, much work is ongoing to try to precisely define the genetic, epigenetic, immunological, and molecular basis of IgA nephropathy. In particular, the precise origin of poorly O-galactosylated IgA1 and the inciting factors for the production of O-glycan-specific antibodies continue to be intensely evaluated. The mechanisms responsible for mesangial IgA1 deposition and subsequent renal injury also remain incompletely understood. In this review, we summarize the current understanding of the key steps involved in the pathogenesis of IgA nephropathy. It is hoped that further advances in our understanding of this common glomerulonephritis will lead to novel diagnostic and prognostic biomarkers, and targeted therapies to ameliorate disease progression.

Differentially expressed long non‑coding RNAs and mRNAs in patients with IgA nephropathy

Long non‑coding RNAs (lncRNAs) have been reported to serve a crucial role in renal diseases; however, their role in immunoglobulin A nephropathy (IgAN) remains unclear. In the present study, peripheral blood mononuclear cells (PBMCs) were collected from both patients with IgAN and healthy controls. A microarray analysis was then performed to identify differentially expressed lncRNAs and mRNAs in PBMCs, which were confirmed by quantitative polymerase chain reaction. In addition, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and lncRNA‑mRNA co‑expression network analyses were conducted. The present study identified 167 differentially expressed lncRNAs and 94 differentially expressed mRNAs. Numerous GO terms, including innate immune response, inflammatory response, IPAF inflammasome complex and UDP‑galactose:β‑N‑acetylglucosamine β‑1, and 3‑galactosyltransferase activity, were significantly enriched in the differentially expressed mRNAs. The top five KEGG signaling pathways included nucleotide‑binding oligomerization domain‑like receptor signaling pathway, hematopoietic cell lineage, inflammatory bowel disease, tumor necrosis factor signaling pathway and other types of O‑glycan biosynthesis. In addition, a total of 149 lncRNAs were shown to interact with 7 mRNAs that were associated with the 'innate immune response' GO term. The results of the present study demonstrated that differentially expressed lncRNAs and mRNAs may have a role in the development of IgAN. These results may aid in the elucidation of a basic pathogenic mechanism, the identification of possible biomarkers and the generation of potential novel treatment strategies for IgAN.

Effect of TLR10 (2322A/G, 720A/C, and 992T/A) polymorphisms on the pathogenesis of Crimean Congo hemorrhagic fever disease

Crimean Congo hemorrhagic fever (CCHF) is a tick-borne disease caused by the Crimean Congo hemorrhagic fever virus (CCHFV). Toll-like receptors (TLRs) are type 1 transmembrane proteins of immune cells that play a critical role in innate and adaptive immunity. The present study first time aims to investigate the relation between TLR10 gene polymorphisms (720A/C, 992T/A, and 2322A/G), severity/non-severity, fatality/non-fatality, and CCFH disease by using PCR-RFLP assay in a Turkish population. TLR10 720A/C polymorphism was determined to be statistically significant both genotype and allele frequency (P = 0,011, P = 0.015, respectively). TLR10 992T/A polymorphism was found statistically significant relationships between patient and control (P = 0.026) and individual with AA genotype have approximately three times greater risk than TT genotype (OR = 2.93). There was not a significant difference in 2322A/G genotype distribution (P = 0.152). There were also statistically significant associations between both TLR10 992T/A and 2322A/G polymorphism and patient mortality (P = 0.001 and P = 0.008, respectively). We have not found statistically any linkage among TLR10 haplotype, but individual AAA and GAT haplotype have higher risk than individual AAT haplotype (OR = 3.22, OR = 1.93, respectively). Consequently, this study shows that pathogenesis of CCHF disease is associated with the TLR10 720A/C and 992T/A polymorphisms. There is a statistically significant association in fatal/non-fatal patients with TLR10 720A/C and 992T/A. The TLR10 992AA genotype might increase and TLR10 720CC genotype might decrease susceptibility to pathogenesis of CCHF disease. TLR 10 polymorphisms may be also an important biomarker for CCHF susceptibility and fatality rate.

Association of Toll-like receptor 10 polymorphisms with autoimmune thyroid disease in Korean children

BACKGROUND

The Toll-like receptors (TLRs) are germline-encoded receptors that play an essential role in initiating the immune response against pathogens. In this study, we assess the association of TLR polymorphism with autoimmune thyroid disease (AITD) in Korean children.

METHODS

We investigated three polymorphisms in the TLR10 gene (rs4129009, rs11096956, and rs10004195) in 85 Korean AITD patients (Graves' disease, [GD]=50, Hashimoto's disease [HD]=35; thyroid-associated ophthalmopathy [TAO]=23, non-TAO=62; male=16, female=69; mean age=13.4±3.1 years) and 279 healthy control subjects.

RESULTS

In patients with AITD, the frequencies of the TLR10 rs4129009 A allele (odds raio [OR]=3.9, corrected p=0.04) and rs10004195 T allele (OR=2.8, corrected p=0.02) were higher than in the healthy controls, whereas the TLR10 rs4129009 GG genotype (OR=0.3, corrected p=0.04) and rs10004195 AA genotype (OR=0.4, corrected p=0.02) showed lower frequencies. The TLR10 rs11096956 did not show any significant association. These significant associations were also found in the non-thyroid-associated ophthalmopathy (TAO) group, but not in the TAO group. The haplotype (AGT) frequency of TLR10 rs4129009, rs11096956, and rs10004195 was higher in the AITD group than in healthy controls (OR=2.1, corrected p=0.03).

CONCLUSIONS

Our results suggest that TLR10 polymorphisms may contribute to the pathogenesis of AITD.

International Union of Basic and Clinical Pharmacology. XCVI. Pattern recognition receptors in health and disease

Since the discovery of Toll, in the fruit fly Drosophila melanogaster, as the first described pattern recognition receptor (PRR) in 1996, many families of these receptors have been discovered and characterized. PRRs play critically important roles in pathogen recognition to initiate innate immune responses that ultimately link to the generation of adaptive immunity. Activation of PRRs leads to the induction of immune and inflammatory genes, including proinflammatory cytokines and chemokines. It is increasingly clear that many PRRs are linked to a range of inflammatory, infectious, immune, and chronic degenerative diseases. Several drugs to modulate PRR activity are already in clinical trials and many more are likely to appear in the near future. Here, we review the different families of mammalian PRRs, the ligands they recognize, the mechanisms of activation, their role in disease, and the potential of targeting these proteins to develop the anti-inflammatory therapeutics of the future.

Toll-like receptor 10-1-6 gene cluster polymorphisms are not associated with benign prostatic hyperplasia in korean population

Purpose

Inflammation and infection have been associated with the pathogenesis of benign prostatic hyperplasia (BPH). Toll-like receptors (TLRs) play key roles in the innate immune system and initiate the inflammatory response to foreign pathogens. We investigated the relationship between TLR10-1-6 gene cluster polymorphisms and BPH.

Methods

We genotyped four promoter single nucleotide polymorphisms (SNPs) (TLR10, rs10004195; TLR1, rs5743557; and TLR6, rs1039560 and rs1039559) by directly sequencing (233 BPH patients and 214 control subjects). SNPStats and Haploview version 4.02 were used to analyze the data. Multiple logistic regression models (log-additive, dominant, and recessive) were performed to determine odds ratios (ORs), 95% confidence intervals (CIs), and P-values.

Results

The genotype and allele frequencies of each SNP was not different between the BPH and control groups (P>0.05). Haplotype analysis showed no association between the haplotype in the linkage disequilibrium (LD) block and BPH (P>0.05), although the LD block was constructed.

Conclusions

These results indicate that the TLR10-1-6 gene cluster may be not associated with the development of BPH in the Korean population.

Allogeneic bone marrow transplantation appears to ameliorate IgA nephropathy in a patient with X-linked thrombocytopenia

Wiskott-Aldrich syndrome (WAS) is caused by a mutation in the WAS gene, and it is clinically characterized by the triad of thrombocytopenia, eczema and immunodeficiency. X-linked thrombocytopenia (XLT), which is a clinically mild form of WAS, is also caused by a WAS gene mutation. Patients with WAS/XLT sometimes also have autoimmune diseases such as IgA nephropathy. Progression of IgA nephropathy may lead to chronic renal failure with a poor prognosis. Here, we describe an XLT patient who also had IgA nephropathy. The patient underwent bone marrow transplantation (BMT) because of an associated-lymphoproliferative disorder, and clinical and histological improvement in his IgA nephropathy was observed after BMT. The amount of galactose-deficient IgA in the patient's serum markedly decreased after BMT. Therefore, immunological reconstitution might improve autoimmune diseases in patients with WAS/XLT.

Toll-like receptors' pathway disturbances are associated with increased susceptibility to infections in humans

Toll-like receptors (TLRs) sense microbial products and play an important role in innate immunity. Currently, 11 members of TLRs have been identified in humans, with important function in host defense in early steps of the inflammatory response. TLRs are present in the plasma membrane (TLR1, TLR2, TLR4, TLR5, TLR6) and endosome (TLR3, TLR7, TLR8, TLR9) of leukocytes. TLRs and IL-1R are a family of receptors related to the innate immune response that contain an intracellular domain known as the Toll-IL-1R (TIR) domain that recruits the TIR-containing cytosolic adapters MyD88, TRIF, TIRAP and TRAM. The classical pathway results in the activation of both nuclear factor κB and MAPKs via the IRAK complex, with two active kinases (IRAK-1 and IRAK-4) and two non-catalytic subunits (IRAK-2 and IRAK-3/M). The classical pro-inflammatory TLR signaling pathway leads to the synthesis of inflammatory cytokines and chemokines, such as IL-1β, IL-6, IL-8, IL-12 and TNF-α. In humans, genetic defects have been identified that impair signaling of the TLR pathway and this may result in recurrent pyogenic infections, as well as virus and fungi infections. In this review, we discuss the main mechanisms of microbial recognition and the defects involving TLRs.

A polymorphism of interleukin-22 receptor alpha-1 is associated with the development of childhood IgA nephropathy

Recent studies suggest that dysregulated innate immunity plays an important role in the pathogenesis of immunoglobulin A nephropathy (IgAN). The interleukin-20 subfamily and its receptor, interleukin-22 receptor alpha-1 (IL-22R1), were recently identified as immunomodulators in human diseases, acting as mediators of mucosal host defense. However, the potential role of IL-22R1 in the pathogenesis of IgAN has not been explored. In the current study, 194 patients with IgAN and 287 normal controls were genotyped for coding polymorphisms of the IL-22R1 gene and the association between the polymorphisms and IgAN was investigated. Local expression of IL-22R1 was examined in patients with IgAN and healthy controls using immunohistochemistry. Our case-control analysis showed that genotypes of rs3795299 were associated with childhood IgAN. Individuals with the CC genotype of rs3795299 had about 3-fold reduced risk of IgAN compared with those with the GG genotype in the codominant model (P=0.0028) and those with the genotypes containing the G allele (GG or GC) in the recessive model (P=0.002). After Bonferroni correction, the association between the rs3795299 CC genotype and reduced risk of developing IgAN remained significant. Furthermore, the renal expression of IL-22R1 was significantly higher in healthy controls compared with subjects with IgAN. Our data suggest that the CC genotype of rs3795299 polymorphism in the IL-22R1 gene is associated with the reduced risk of IgAN, and this genetic association was supported by the higher renal expression of IL-22R1 in healthy controls compared with patients with IgAN.

Clinicopathological and immunohistological features in childhood IgA nephropathy: a single-centre experience

Background

IgA nephropathy is a glomerular disease diagnosed by renal biopsy and is characterized by a highly variable course ranging from a completely benign condition to rapidly progressive renal failure. We aimed to evaluate the clinical, histopathological and inflammatory characteristics of children with IgA nephropathy.

Methods

Data of 37 patients with IgA nephropathy diagnosed between the years 1980 and 2008 were retrospectively reviewed. Immunohistochemistry was performed in 24 patients. Expression of CD3, CD4, CD8, CD20, CD68, IL-1β, IL-10, IL-17, TGF-β, TNF-α and the newly proposed tubulointerstitial fibrosis marker nestin were evaluated.

Results

The median age at diagnosis was 10 years. Recurrent macroscopic haematuria (66%) was the most common clinical manifestation, and 35% of the patients had synpharyngitic presentation. A significant correlation was found between proteinuria and increase in mesangial matrix (r = 0.406, P = 0.013). The presence of CD4+ T lymphocytes and CD68+ macrophages were also significantly associated with proteinuria >1 g/day. While cytokines IL-1β, IL-10 and TNF-α were mainly expressed in tubular epithelial cells, TGF-β was evident in glomeruli but they had no correlation to clinical features and severity of the disease. Nestin was detected at the tubules in almost half of the patients with no correlation to proteinuria and tubulointersititial fibrosis.

Conclusions

We found a correlation between proteinuria and mesangial matrix expansion. The presence of CD4+ T-lymphocytes and CD68+ macrophages were also significantly associated with proteinuria >1 g/day. Although there are many evidences, for immunological basis of IgA nephropathy, the immunological markers were not fully expressed in children to evaluate glomerular and tubulointerstitial inflammation, and progression of the disease. Further studies with the extended number of children are needed to shed light on the immunological basis of the disease.

Toll-like receptors of deuterostome invertebrates

Defensive systems against pathogens are responsible not only for survival or lifetime of an individual but also for the evolution of a species. Innate immunity is expected to be more important for invertebrates than mammals, given that adaptive immunity has not been acquired in the former. Toll-like receptors (TLRs) have been shown to play a crucial role in host defense of pathogenic microbes in innate immunity of mammals. Recent genome-wide analyses have suggested that TLR or their related genes are conserved in invertebrates. In particular, numerous TLR-related gene candidates were detected in deuterostome invertebrates, including a sea urchin (222 TLR-related gene candidates) and amphioxus (72 TLR-related gene candidates). Molecular phylogenetic analysis verified that most of sea urchin or amphioxus TLR candidates are paralogous, suggesting that these organisms expanded TLR-related genes in a species-specific manner. In contrast, another deuterostome invertebrate, the ascidian Ciona intestinalis, was found to possess only two TLR genes. Moreover, Ciona TLRs, Ci-TLR1 and Ci-TLR2, were shown to possess “hybrid” functionality of mammalian TLRs. Such functionality of Ci-TLRs could not be predicted by sequence comparison with vertebrate TLRs, indicating confounding evolutionary lineages of deuterostome invertebrate TLRs or their candidates. In this review article, we present recent advances in studies of TLRs or their candidates among deuterostome invertebrates, and provide insight into an evolutionary process of TLRs.