Association between polymorphisms in the Toll-like receptor 4, CD14, and CARD15/NOD2 and inflammatory bowel disease in the Greek population

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.

Gut microbiota and transcriptome profiling revealed the protective effect of aqueous extract of Tetrastigma hemsleyanum leaves on ulcerative colitis in mice

Tetrastigma hemsleyanum, a traditional Chinese medicinal plant, possesses various biological activities, including anti-inflammatory and immunomodulatory functions. The purpose of this study was to determine the alleviating effect of the water extract of Tetrastigma hemsleyanum leaves (THLW) on ulcerative colitis (UC) and its relationship with gut microbiota. The administration of THLW significantly decreased the severity of dextran sulfate sodium (DSS)-induced intestinal damage, as demonstrated by the stabilization of body weight and colon length, and decreased disease activity index (DAI) and histological scores. THLW also decreased NF-κB protein expression in colon tissues and reduced the serum levels of IL-6, IL-1β, and TNF-α. Further co-housing experiment confirmed that the anti-UC effect of THLW was possibly by regulating the structure and composition of gut microbiota, including increasing the abundance of Oscillospiraceae, Prevotellaceae and Corynebacterium. Additionally, the expression of genes related to inflammation and immunity was also regulated by THLW treatment as evidenced by transcriptome analysis. These results suggested that the protective effect of THLW on DSS-induced colitis was mediated by alleviating inflammation and modulating the microbiota composition. This work proved the potent protective effects of THLW treatment on colitis and may have potential for UC relief.

NOD1 and NOD2 Are Potential Therapeutic Targets for Cancer Immunotherapy

The nucleotide oligomerization domain (NOD)-like receptors (NLRs) are a group of intracellular proteins that are essential for controlling the host's innate immune response. The cytosolic nucleotide binding oligomerization domains 1 and 2 receptors (NOD1 and NOD2) are the most widely investigated NLRs. As pattern recognition receptors (PRRs), NOD1 and NOD2 may recognize and bind endogenous damage associated molecular patterns (DAMPs) and external pathogenic associated molecular patterns (PAMPs), directing the activation of inflammatory caspases through engaging the adaptor protein RIP2, which further activates the NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways, thereby mediating host innate immunity and regulating the adaptive immunity. Previous research has identified NOD1 and NOD2 as key players in inflammatory disease and host-microbial defense. Despite numerous studies claiming that NOD1 and NOD2 are linked to tumorigenesis and tumor development, it is still unclear whether NOD1 and NOD2 act as cancer's friends or foes. In this review, we focus on concluding the current research progress on the role of NOD1 and NOD2 in a variety of cancers and discussing the potential reasons for the contradicting role of NOD1 and NOD2 in cancers. This review may help better understand the role of NOD1 and NOD2 in cancer and shed light on NOD1 and NOD2 as potential therapeutic targets for tumor immunotherapy.

Intestinal Inflammation and Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease which significantly influences the life quality of patients. The protein α-synuclein plays an important driving role in PD occurrence and development. Braak's hypothesis suggests that α-synuclein is produced in intestine, and then spreads into the central nervous system through the vagus nerve. The abnormal expression of α-synuclein has been found in inflammatory bowel disease (IBD). Intestinal inflammation and intestinal dysbiosis have been involved in the occurrence and development of PD. The present review aimed to summarize recent advancements in studies focusing on intestinal inflammation and PD, especially the mechanisms through which link intestinal inflammation and PD. The intestinal dysfunctions such as constipation have been introduced as non-motor manifestations of PD. The possible linkages between IBD and PD, including genetic overlaps, inflammatory responses, intestinal permeability, and intestinal dysbiosis, are mainly discussed. Although it is not confirmed whether PD starts from intestine, intestinal dysfunction may affect intestinal microenvironment to influence central nervous system, including the α-synuclein pathologies and systematic inflammation. It is expected to develop some new strategies in the diagnosis and treatment of PD from the aspect of intestine. It may also become an exciting direction to find better ways to regulate the composition of gut microorganism to treat PD.

Crohn's Disease Susceptibility and Onset Are Strongly Related to Three NOD2 Gene Haplotypes

The genetic background and the determinants influencing the disease form, course, and onset of inflammatory bowel disease (IBD) remain unresolved. We aimed to determine the NOD2 gene haplotypes and their relationship with IBD occurrence, clinical presentation, and onset, analyzing a cohort of 578 patients with IBD, including children, and 888 controls. Imaging or endoscopy with a histopathological confirmation was used to diagnose IBD. Genotyping was performed to assess the differences in genotypic and allelic frequencies. Linkage disequilibrium was analyzed, and associations between haplotypes and clinical data were evaluated. We emphasized the prevalence of risk alleles in all analyzed loci in patients with Crohn disease (CD). Interestingly, c.2722G>C and c.3019_3020insC alleles were also overrepresented in ulcerative colitis (UC). T-C-G-C-insC, T-C-G-T-insC, and T-T-G-T-wt haplotypes were correlated with the late-onset form of CD (OR = 23.01, 5.09, and 17.71, respectively), while T-T-G-T-wt and C-C-G-T-wt were prevalent only in CD children (OR = 29.36, and 12.93, respectively; p-value = 0.001). In conclusion, the presence of c.3019_3020insC along with c.802C>T occurred as the most fundamental contributing diplotype in late-onset CD form, while in CD children, the mutual allele in all predisposing haplotypes was the c.2798 + 158T. Identifying the unique, high-impact haplotypes supports further studies of the NOD2 gene, including haplotypic backgrounds.

Association Between TLR4 Gene Polymorphisms and Risk of Preeclampsia: Systematic Review and Meta-Analysis

BACKGROUND Toll-like receptor 4 (TLR4) plays a pivotal role in the innate immune response and is hyperactivated in preeclampsia (PE). Several researchers have published conflicting evidence for TLR4 rs4986790 and rs4986791 single nucleotide polymorphisms (SNPs) as risk factors for PE. The present meta-analysis was conducted to obtain a more definitive conclusion about the effects of these SNPs on PE susceptibility. MATERIAL AND METHODS To determine the correlation between rs4986790 and rs4986791 polymorphisms in the TLR4 gene and susceptibility to PE, the PubMed, Web of Science, EMBASE, Chinese National Knowledge Infrastructure, and Chinese WANFANG databases were searched for eligible articles. Statistical analysis was performed with STATA software, version 12.0. Pooled odds ratios with corresponding 95% confidence intervals (CIs) were extracted for assessment of correlation strength. RESULTS We identified 5 studies including 578 cases and 631 controls for the rs4986790 SNP and 4 studies including 469 cases and 457 controls for the rs4986791 SNP, mainly from a White population. The pooled analyses showed no statistical relationship between the polymorphisms rs4986790 and rs4986791 and PE susceptibility in 5 genetic models (all P>0.05). Moreover, the allelic and dominant gene models of rs4986790 and the allelic, heterozygous, and dominant gene models of rs4986791 had high heterogeneity. The sensitivity analysis explored potential sources of heterogeneity and confirmed the findings of this meta-analysis. CONCLUSIONS TLR4 rs4986790 and rs4986791 polymorphisms may not be implicated in PE susceptibility, primarily in a White population. More high-quality studies of genetic associations with PE are warranted.

Human Genetic Variation Influences Enteric Fever Progression

In the 21st century, enteric fever is still causing a significant number of mortalities, especially in high-risk regions of the world. Genetic studies involving the genome and transcriptome have revealed a broad set of candidate genetic polymorphisms associated with susceptibility to and the severity of enteric fever. This review attempted to explain and discuss the past and the most recent findings on human genetic variants affecting the progression of Salmonella typhoidal species infection, particularly toll-like receptor (TLR) 4, TLR5, interleukin (IL-) 4, natural resistance-associated macrophage protein 1 (NRAMP1), VAC14, PARK2/PACRG, cystic fibrosis transmembrane conductance regulator (CFTR), major-histocompatibility-complex (MHC) class II and class III. These polymorphisms on disease susceptibility or progression in patients could be related to multiple mechanisms in eliminating both intracellular and extracellular Salmonella typhoidal species. Here, we also highlighted the limitations in the studies reported, which led to inconclusive results in association studies. Nevertheless, the knowledge obtained through this review may shed some light on the development of risk prediction tools, novel therapies as well as strategies towards developing a personalised typhoid vaccine.

Necrotizing Enterocolitis: LPS/TLR4-Induced Crosstalk Between Canonical TGF-β/Wnt/β-Catenin Pathways and PPARγ

Necrotizing enterocolitis (NEC) represents one of the major causes of morbidity and mortality in premature infants. Several recent studies, however, have contributed to a better understanding of the pathophysiology of this dreadful disease. Numerous intracellular pathways play a key role in NEC, namely: bacterial lipopolysaccharide (LPS), LPS toll-like receptor 4 (TLR4), canonical Wnt/β-catenin signaling and PPARγ. In a large number of pathologies, canonical Wnt/β-catenin signaling and PPARγ operate in opposition to one another, so that when one of the two pathways is overexpressed the other is downregulated and vice-versa. In NEC, activation of TLR4 by LPS leads to downregulation of the canonical Wnt/β-catenin signaling and upregulation of PPARγ. This review aims to shed light on the complex intracellular mechanisms involved in this pathophysiological profile by examining additional pathways such as the GSK-3β, NF-κB, TGF-β/Smads, and PI3K-Akt pathways.

Atherosclerosis and Inflammatory Bowel Disease-Shared Pathogenesis and Implications for Treatment

Atherosclerosis and inflammatory bowel disease (IBD) are often regarded as 2 distinct entities. The commonest manifestation of atherosclerosis is ischemic heart disease (IHD), and an association between IHD and IBD has been reported. Atherosclerosis and IBD share common pathophysiological mechanisms in terms of their genetics, immunology, and contributing environmental factors. Factors associated with atherosclerosis are implicated in the development of IBD and vice versa. Therefore, treatments targeting the common pathophysiology pathways may be effective in both conditions. The current review considers the pathophysiological pathways that are shared between the 2 conditions and discusses the implications for treatment and research.

Impact of Historic Migrations and Evolutionary Processes on Human Immunity

The evolution of mankind has constantly been influenced by the pathogens encountered. The various populations of modern humans that ventured out of Africa adapted to different environments and faced a large variety of infectious agents, resulting in local adaptations of the immune system for these populations. The functional variation of immune genes as a result of evolution is relevant in the responses against infection, as well as in the emergence of autoimmune and inflammatory diseases observed in modern populations. Understanding how host-pathogen interactions have influenced the human immune system from an evolutionary perspective might contribute to unveiling the causes behind different immune-mediated disorders and promote the development of new strategies to detect and control such diseases.

Genetic diversity of CD14, CD28, CTLA-4 and ICOS gene promoter polymorphism in African and American sickle cell disease

Variable immune response to external stimuli remains a major concern in sickle cell disease (SCD), with such responses predicted to be contributors to disease pathogenesis. Elucidating the diversity of host genes contributing to immune response would assist to clarify differing outcomes among and between disease groups. We hypothesize that there is a significant interethnic diversity in the CD14 (rs2569190), CD28 (rs35593994), CTLA-4 (rs5742909) and ICOS (rs4404254) gene polymorphisms among and between SCD groups. We genotyped single nucleotide polymorphisms of the 4 loci among African and African American SCD and control groups and between SCD groups. In all, 375 individuals from Mali (145 SCD and 230 controls) and 700 DNA samples from the United States (321 SCD and 379 controls) were subjected to a PCR-RFLP assay. We found no intraethnic difference in genotypic and allelic frequencies of the 4 loci among Africans and African Americans, potentially significant in disease association studies, including a similar observation for interethnic frequencies of CD28, CTLA-4 and ICOS genes, but not CD14. The CD14 (rs2569190) gene promoter demonstrated a significant difference (p < 0.02) between African and African American SCD groups, with the mutant variant (-159 T/T) more frequent (p < 0.0002) in African American SCD (38.9% versus 26.2%). The higher frequency of CD14 mutants among African Americans without an accompanying defect in CD28, CTLA-4 and ICOS diversity possibly indicates a defective innate response, driven by CD14, is untethered to downstream T cell differentiation or effector function. Additionally, we show that CD28 (rs35593994) mutant variants have no impact on T cell differentiation, as the ICOS gene provides an alternative pathway to override this impairment. We conclude that in spite of the defect in CD14, T cell selection and differentiation is unimpeded and a robust adaptive immune response initiated.

Differential genetic and functional background in inflammatory bowel disease phenotypes of a Greek population: a systems bioinformatics approach

Background

Crohn’s disease (CD) and Ulcerative colitis (UC) are the two main entities of inflammatory bowel disease (IBD). Previous works have identified more than 200 risk factors (including loci and signaling pathways) in populations of predominantly European ancestry. Our study was conducted on an extended population-specific cohort of 573 Greek IBD patients (364 CD and 209 UC) and 445 controls.

Aims

To highlight the different genetic and functional background of IBD and its phenotypes, utilizing contemporary systems bioinformatics methodologies.

Methods

Disease-associated SNPs, obtained via our own 89 loci IBD risk GWAS panel, were detected with the whole genome association analysis toolset PLINK. These SNPs were used as input for 2 novel and different pathway analysis methods to detect functional interactions. Specifically, PathwayConnector was used to create complementary networks of interacting pathways whereas; the online database of protein interactions STRING provided protein–protein association networks and their derived pathways. Network analyses metrics were employed to identify proteins with high significance and subsequently to rank the signaling pathways those participate in.

Results

The reported complementary pathway and enriched protein–protein association networks reveal several novel and well-known key players, in the functional background of IBD like Toll-like receptor, TNF, Jak-STAT, PI3K-Akt, T cell receptor, Apoptosis, MAPK and B cell receptor signaling pathways. IBD subphenotypes are found to have distinct genetic and functional profiles which can contribute to their accurate identification and classification. As a secondary result we identify an extended network of diseases with common molecular background to IBD.

Conclusions

IBD’s burden on the quality of life of patients and intricate functional background presents us constantly with new challenges. Our data and methodology provide researchers with new insights to a specific population, but also, to possible differentiation markers of disease classification and progression. This work, not only provides new insights into the interplay among IBD risk variants and their related signaling pathways, elucidates the mechanisms underlying IBD and its clinical sequelae, but also, introduces a generalized bioinformatics-based methodology which can be applied to studies of different disorders.

Electronic supplementary material

The online version of this article (10.1186/s13099-019-0312-y) contains supplementary material, which is available to authorized users.

Toll-like receptor polymorphism in host immune response to infectious diseases: A review

Immunopolymorphism is considered as an important aspect behind the resistance or susceptibility of the host to an infectious disease. Over the years, researchers have explored many genetic factors for their role in immune surveillance against infectious diseases. Polymorphic characters in the gene encoding Toll-like receptors (TLRs) play profound roles in inducing differential immune responses by the host against parasitic infections. Protein(s) encoded by TLR gene(s) are immensely important due to their ability of recognizing different types of pathogen associated molecular patterns (PAMPs). This study reviews the polymorphic residues present in the nucleotide or in the amino acid sequence of TLRs and their influence on alteration of inflammatory signalling pathways promoting either susceptibility or resistance to major infectious diseases, including tuberculosis, leishmaniasis, malaria and filariasis. Population-based studies exploring TLR polymorphisms in humans are primarily emphasized to discuss the association of the polymorphic residues with the occurrence and epidemiology of the mentioned infectious diseases. Principal polymorphic residues in TLRs influencing immunity to infection are mostly single nucleotide polymorphisms (SNPs). I602S (TLR1), R677W (TLR2), P554S (TLR3), D299G (TLR4), F616L (TLR5), S249P (TLR6), Q11L (TLR7), M1V (TLR8), G1174A (TLR9) and G1031T (TLR10) are presented as the major influential SNPs in shaping immunity to pathogenic infections. The contribution of these SNPs in the structure-function relationship of TLRs is yet not clear. Therefore, molecular studies on such polymorphisms can improve our understanding on the genetic basis of the immune response and pave the way for therapeutic intervention in a more feasible way.

Association between Toll-Like Receptor 4 T399I Gene Polymorphism and the Susceptibility to Crohn's Disease: A Meta-Analysis of Case-Control Studies

BACKGROUND/AIMS

This article was undertaken to investigate the association of toll-like receptor 4 (TLR4) polymorphism (Thr399Ile) and risk of Crohn's disease (CD) by performing a meta-analysis.

METHODS

Articles were chosen based on PubMed, Embase, China National Knowledge Internet, and Chinese Wanfang databases (up to 12th October 2016). Specific inclusion criteria were used to evaluate articles. Meta-analysis was performed by using a random or fixed effect model. Fifteen eligible case-control studies were finally included into this meta-analysis. We estimated the summary OR with its corresponding 95% CI to assess the association.

RESULTS

Summary results of this meta-analysis showed a moderate association between the TLR4 T399I polymorphism and the risk of CD (allele model: OR 1.26, 95% CI 1.06-1.50, p = 0.009; heterozygote model: OR 1.36, 95% CI 1.11-1.66, p = 0.003; dominant model: OR 1.35, 95% CI 1.10-1.64, p = 0.004; homozygote model: OR 1.08, 95% CI 0.44-2.64, p = 0.866; recessive model: OR 0.97, 95% CI 0.40-2.35, p = 0.946). Stratified analysis on geographical area, ethnicity, and genotypic methods suggested that the polymorphism was associated with increased risk of CD in Asia and Asians, and "T" allele only moderately increased CD risk within polymerase chain reaction-restricted fragment length polymorphism.

CONCLUSIONS

Our meta-analysis suggests that TLR4 T399I polymorphism is moderately associated with susceptibility to CD, and more studies are needed to confirm our conclusion.

Role of toll-like receptors in inflammatory bowel disease

Inflammatory bowel disease (IBD) is the chronic inflammation of the gastrointestinal tract. Recently, studies of the interplay between the adaptive and innate immune responses have provided a better understanding of the immunopathogenesis of inflammatory disorders such as IBD, as well as identification of novel targets for more potent interventions. Toll-like receptors (TLRs) are a class of proteins that play a significant role in the innate immune system and are involved in inflammatory processes. Activation of TLR signal transduction pathways lead to the induction of numerous genes that function in host defense, including those for inflammatory cytokines, chemokines, and antigen presenting molecules. It was proposed that TLR mutations and dysregulation are major contributing factors to the predisposition and susceptibility to IBD. Thus, modulating TLRs represent an innovative immunotherapeutic approach in IBD therapy. This article outlines the role of TLRs in IBD, focusing on both animal and human studies; the role of TLR-targeted agonists or antagonists as potential therapeutic agents in the different stages of the disease is discussed.

Genetic association and phenotypic correlation of TLR4 but not NOD2 variants with Tunisian inflammatory bowel disease

OBJECTIVE

The common association between NOD2/CARD15 and TLR4 gene variants with inflammatory bowel disease (IBD) has not been replicated in all studies. We studied the polymorphism of these two genes in Tunisian patients with IBD.

METHODS

Polymorphisms of NOD2 (R702W, G908R and L1007fs) and TLR4 (Asp299Gly and Thr399Ile) genes were analyzed in 106 patients with IBD (68 with ulcerative colitis [UC], 38 with Crohn's disease [CD]) and 160 healthy controls using polymerase chain reaction-restriction fragment length polymorphism. Genotypes and phenotypes were correlated.

RESULTS

The mutated allele of TLR4-Thr399Ile was strongly associated with IBD (9.4% in IBD, 7.4% in UC and 13.2% in CD vs 2.5% in controls; P = 0.0004, 0.014 and 0.00006, respectively). Heterozygous genotypes were significantly more frequent in patients with IBD (17.0%), UC (14.7%) and CD (21.1%) than in controls (5.0%) (P = 0.0012, 0.012 and 0.001, respectively). Interestingly, the wild genotype was found to be protective (odds ratio 0.24). The mutated allele of TLR4-Asp299Gly was more frequent in controls (6.8%) than in patients with IBD (2.9%). A phenotypic correlation of Asp299Gly-AG genotype with arthritis in UC patients was detected (P = 0.003). Regarding the NOD2 gene, the common variations studied were not polymorphic and there was no genetic association with IBD.

CONCLUSION

The TLR4-Thr399Ile variant was strongly associated with susceptibility to IBD, whereas TLR4-Asp299Gly seems to play a role in the clinical expression of UC. The rarity and non-association of NOD2 mutations with IBD may reveal a genetic characteristic of the population in our region.

Genetic Diversity of CD14 Promoter Gene Polymorphism (rs2569190) is Associated With Regulation of Malaria Parasitemia and Susceptibility to Plasmodium falciparum Infection

CD14 is a multifunctional receptor expressed on many cell types and has been shown to mediate immune response resulting in the activation of an inflammatory cascade, with polymorphism of its promoter (rs2569190) found to be associated with susceptibility to several diseases. In malaria infection, the CD14 gene demonstrated a pathogenic profile in regulating experimental cerebral malaria, with reports of elevated levels of soluble CD14 in serum of patients but no definitive conclusion. We present a detailed analysis of genetic diversity of CD14 promoter gene (snp −159 C/T; rs2519190) polymorphism between a malaria-infected group and uninfected controls and its association with clinical parameters of disease. Genomic DNA samples obtained from 106 Plasmodium falciparum malaria–infected patients and 277 uninfected controls were elucidated with a polymerase chain reaction-restriction fragment length polymorphism (RFLP) assay. Our results show a significant diversity (P = 3.32E−06) in the genotypic frequency (3.8% versus 22.4%) of the rs2569190 mutant variant between the malaria-infected group and controls, respectively. The mutant allele had the lowest frequency among the malaria-infected group demonstrating its necessity for infection. Mean parasitemia (parasites/μL of blood) was significantly regulated based on CD14 polymorphic profile (19 855 versus 37 041 versus 49 396 for homozygote mutants, heterozygotes, and homozygote wild type, respectively). Interestingly, we found no association between CD14 genetic variants with fever, age of patients, or anemia. How this affects disease severity between subregional and continental groups deserves further clarification, including extending these studies in a larger group and among severe and asymptomatic patients with malaria.

Genetic Variability as a Regulator of TLR4 and NOD Signaling in Response to Bacterial Driven DNA Damage Response (DDR) and Inflammation: Focus on the Gastrointestinal (GI) Tract

The fundamental role of human Toll-like receptors (TLRs) and NOD-like receptors (NLRs), the two most studied pathogen recognition receptors (PRRs), is the protection against pathogens and excessive tissue injury. Recent evidence supports the association between TLR/NLR gene mutations and susceptibility to inflammatory, autoimmune, and malignant diseases. PRRs also interfere with several cellular processes, such as cell growth, apoptosis, cell proliferation, differentiation, autophagy, angiogenesis, cell motility and migration, and DNA repair mechanisms. We briefly review the impact of TLR4 and NOD1/NOD2 and their genetic variability in the process of inflammation, tumorigenesis and DNA repair, focusing in the gastrointestinal tract. We also review the available data on new therapeutic strategies utilizing TLR/NLR agonists and antagonists for cancer, allergic diseases, viral infections and vaccine development against both infectious diseases and cancer.

Association between the -159C/T polymorphism in the promoter region of the CD14 gene and sepsis: a meta-analysis

Background

The association between CD14-159C/T polymorphism and sepsis has been assessed but results of current studies appeared conflicting and inconstant. This analysis was aimed to determine whether the CD14-159C/T polymorphism confers susceptibility to sepsis or is associated with increased risk of death from sepsis.

Method

The authors conducted a comprehensive search of PubMed, EMBASE, ISI Web of Science, Cochrane library, ScienceDirect, Wiley Online Library and CNKI databases according to a prespecified protocol. Language limits were restricted to English and Chinese. Two reviewers independently selected the articles and extracted relevant data onto standardized forms. Disagreements were settled by discussion and suggestions from senior consultants. The strength of association were evaluated by odds ratio (OR) and 95% confidence interval (CI). Studies failed to fit the Hardy-Weinberg-Equilibrium were excluded.

Results

The research identified a total of 2317 full-text articles of which 14 articles met the predefined inclusion criteria. Meta-analysis was performed for allele frequency of C versus T, as well as genotypes CC + CT versus TT (dominant model), CC versus TT + CT (recessive model), CT versus TT and CC versus TT (additive model). All control samples were in Hardy-Weinberg proportion. No significant association between CD14-159C/T polymorphism and sepsis susceptibility or mortality were detected in the overall population. Nonetheless, subgroup analysis of Asian ethnicity revealed significant association between the CD14-159C/T polymorphism and susceptibility to sepsis in additive model (CC versus TT: OR = 0.52, 95% CI 0.29–0.92, p = 0.03) and recessive model (CC versus CT + TT: OR = 0.50, 95% CI 0.30–0.84, p = 0.009). Of note, three out of the five papers included in the subgroup focused exclusively on burn ICU patients.

Conclusions

This meta-analysis demonstrated that CD14-159C/T polymorphism is likely to be associated with susceptibility to sepsis in Asian population, especially for the TT genotype. However, bias may rise for etiologic reasons because the majority of subjects in the subgroup came from burn ICU. CD14-159C/T polymorphism is not relevant to sepsis mortality in any genetic models, regardless of the ethnicities. Due to the exploratory nature of the study, no adjustment for multiple testing was adopted, and therefore the results should be interpreted with precaution. Well-designed studies with larger sample size and more ethnic groups are required to further validate the results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-017-0303-9) contains supplementary material, which is available to authorized users.

Intestinal Bacteria Composition and Translocation of Bacteria in Inflammatory Bowel Disease

BACKGROUND

Live commensal intestinal bacteria are present in the peripheral blood where they can induce inflammation.

OBJECTIVE

To evaluate the intestinal bacteria composition and translocation of bacteria in IBD.

METHODS

Both blood and tissue biopsy samples were collected from adult patients with active/inactive Crohn's disease (CD), active/inactive ulcerative colitis (UC) and healthy individuals. Most of the patients were newly diagnosed and none of them received antibiotics. Using a reverse transcription-quantitative real-time PCR (RT-qPCR) method, we determined the composition of microbiota. NOD2/CARD15 genotyping was also studied.

RESULTS

Total bacterial DNA concentration was increased in tissue and blood samples of IBD patients compared to healthy controls. Furthermore, the active IBD cases had higher total bacterial DNA concentration levels compared to the inactive cases. Three species characterized dysbiosis in IBD, namely an increase of Bacteroides spp in active and inactive IBD samples, and a decrease in Clostridium leptum group (IV), and Faecalibacterium prausnitzi in both active and inactive IBD patients. No significant association between bacterial translocation and NOD2/CARD15 mutations was found.

CONCLUSIONS

The composition of the microbiota in IBD patients differs from that of healthy controls. The high rate of bacterial DNA in the blood samples indicates translocation in inflammatory bowel disease.

Functional dyspepsia susceptibility is related to CD14, GNB3, MIF, and TRPV1 gene polymorphisms in the Greek population

BACKGROUND

Functional dyspepsia (FD) susceptibility might be influenced by polymorphisms of genes related to inflammation (CD14, macrophage migration inhibitory factor [MIF]), motor (GNB3), and sensory dysfunction (GNB3, TRPV1). We examined the association between CD14 rs2569190, GNB3 rs5443, MIF rs222747, and TRPV1 rs755622 gene polymorphisms with FD (Rome III criteria) in the Greek population.

METHODS

We genotyped 174 dyspeptics (115 with epigastric pain syndrome; 41% Helicobacter pylori positive) and 181 controls using polymerase chain reaction-based methods and we measured disease symptoms' burden with a modified Gastrointestinal Symptoms Related Scale.

KEY RESULTS

Homozygous for the TT genotype and the T allele of the CD14 gene were significantly associated (OR [95% CI]) with FD (2.65 [1.42-4.94] and 1.67 [1.23-2.26], respectively). The CT, TT genotypes, and T allele frequencies of GNB3 showed also significant association with FD (2.18 [1.35-3.54], 3.46 [1.30-9.23], and 2.18 [1.48-3.19]). While heterozygous GC MIF genotype was more common in dyspeptics (1.67 [1.07-2.60]), homozygous CC genotype and the C allele of TRPV1 gene were more prevalent in controls (0.47 [0.25-0.87] and 0.69 [0.51-0.92], respectively). None of the gene polymorphism was related either to dyspepsia clinical syndrome type or to the H. pylori infection. Among dyspeptics, CD14 TT genotype was related to lower epigastric pain burden score (p<.011); CD14 CT genotype was related to higher epigastric burning and nausea burden scores (p<.04) while belching score was lower (p=.027) in MIF CG dyspeptics.

CONCLUSION & INFERENCES

Functional dyspepsia susceptibility is related to CD14, GNB3, MIF, and TRPV1 gene polymorphisms, while CD14 and MIF gene variants are also associated with dyspepsia symptoms burden.

Epistatic interaction between TLR4 and NOD2 in patients with Crohn's Disease: relation with risk and phenotype in a Spanish cohort

Crohn's Disease is one of the two major forms of the Inflammatory Bowel Diseases and, although the etiology is not completely understood, the confluence of environmental and genetic factors has been demonstrated. The aim of this study was to determine the distribution of TLR4 variants in a Spanish cohort of Crohn's Disease patients and their relation with phenotype and common NOD2 variants. A total of 371 Crohn's Disease (CD) patients and 636 healthy controls (HC) were included. Single Nucleotide Polimorphisms (SNPs) in TLR4 (D299G and T399I) and NOD2 (R702W and G908R) detection was performed by a Taqman(®) Allelic Discrimination Assay. 1007insC NOD2 variant was analyzed using a PCR combined with fluorescent technology and the different alleles were determined depending on the PCR products size. D299G and T399I were related to CD only in patients carrying NOD2 variants (NOD2+/TLR4+ haplotype) (p=0.036; OR=1.924), increasing the risk to develop CD when 1007insC and TLR4 variants were both present (OR=4.886). We also described a strong association between mutant NOD2 and CD risk (p<0.001, OR=3.214). R702W, G908R and 1007insC were associated when they were considered separately (p<0.001; p=0.002; p<0.001, respectively). Moreover, the patients carrying any mutant D299G or T399I polymorphisms were predisposed to develop a stricturing disease (p=0.013; OR=2.391), especially in the presence of NOD2 mutation (p=0.002; OR=4.989). In this study, ileal disease was also associated with the presence of at least one NOD2 susceptibility allele (p=0.001; OR=3.838) and, the risk of ileal CD was increased if TLR4 variants were presents (p<0.050; OR=4.160). TLR4 variants were related to bowel perforation, independently of NOD2.

TLR-4 and CD14 Genotypes and Soluble CD14: Could They Predispose to Coronary Atherosclerosis?

Background: Inflammatory mechanisms are key to the pathogenesis of atherosclerosis. Functional polymorphisms of TLR-4, Asp299Gly and Thr399Ile, CD14 promoter area C260T polymorphism and plasma levels of soluble CD14 are studied in subjects with Coronary Artery Disease (CAD). Methods: DNA was obtained from 100 human paraffin-embedded aortic specimens, from cadavers with known coronary atheromatosis (Group A) and 100 blood samples from patients with CAD, as detected by cardiac Multi-Detector-row-Computed-Tomography (MDCT) (Group B). Our control group consisted of 100 healthy individuals (Group C). Genotyping was performed by Restriction Fragment Length Polymorphism-Polymerase Chain Reaction (RFLP-PCR). Plasma levels of sCD14 were measured with ELISA. Results: For TLR-4 Asp299Gly and Thr399Ile polymorphisms, no statistically significant differences were observed. Regarding the C260T polymorphism, frequencies of T allele were significantly higher in the control group compared to the case group (p = 0.05). The Odds Ratio (OR) showed statistically significant association of TT genotype with healthy individuals (OR 0.25, 95% Confidence Interval CI 0.10–0.62, p = 0.0017). Plasma levels of sCD14 in patients with CAD (mean value = 1.35 μg/mL) were reduced when compared to reference value. Conclusions: The studied polymorphisms ofTLR-4 showed no association with CAD. Conversely, the functional polymorphism of CD14 has a statistically significant difference in expression between healthy and affected by CAD individuals.

Next-generation sequencing and its initial applications for molecular diagnosis of systemic auto-inflammatory diseases

OBJECTIVES

Systemic auto-inflammatory disorders (SAIDs) are a heterogeneous group of monogenic diseases sharing a primary dysfunction of the innate immune system. More than 50% of patients with SAID does not show any mutation at gene(s) tested because of lack of precise clinical classification criteria and/or incomplete gene screening. To improve the molecular diagnosis and genotype interpretation of SAIDs, we undertook the development of a next-generation sequencing (NGS)-based protocol designed to simultaneous screening of 10 genes.

METHODS

Fifty patients with SAID, already genotyped for the respective causative gene(s), were massively sequenced for the coding portions of MEFV, MVK, TNFRSF1A, NLRP3, NLRP12, NOD2, PSTPIP1, IL1RN, LPIN2 and PSMB8. Three different bioinformatic pipelines (Ion Reporter, CLC Bio Genomics Workbench, GATK-based in-house workflow) were compared.

RESULTS

Once resulting variants were compared with the expected mutation list, no workflow turned out to be able to detect all the 79 variants known in the 50 DNAs. Additional variants were also detected, validated by Sanger sequencing and compared to assess true and false positive detection rates of the three workflows. Finally, the overall clinical picture of 34 patients was re-evaluated in the light of the new mutations found.

CONCLUSIONS

The present gene panel has resulted suitable for molecular diagnosis of SAIDs. Moreover, genotype-phenotype correlation has confirmed that the interpretation of NGS data in patients with an undefined inflammatory phenotype is remarkably difficult, thus supporting the need of evidence-based and validated clinical criteria to be used concurrently with the genetic analysis for the final diagnosis and classification of patients with SAIDs.

The DNA damage response and immune signaling alliance: Is it good or bad? Nature decides when and where

The characteristic feature of healthy living organisms is the preservation of homeostasis. Compelling evidence highlight that the DNA damage response and repair (DDR/R) and immune response (ImmR) signaling networks work together favoring the harmonized function of (multi)cellular organisms. DNA and RNA viruses activate the DDR/R machinery in the host cells both directly and indirectly. Activation of DDR/R in turn favors the immunogenicity of the incipient cell. Hence, stimulation of DDR/R by exogenous or endogenous insults triggers innate and adaptive ImmR. The immunogenic properties of ionizing radiation, a prototypic DDR/R inducer, serve as suitable examples of how DDR/R stimulation alerts host immunity. Thus, critical cellular danger signals stimulate defense at the systemic level and vice versa. Disruption of DDR/R-ImmR cross talk compromises (multi)cellular integrity, leading to cell-cycle-related and immune defects. The emerging DDR/R-ImmR concept opens up a new avenue of therapeutic options, recalling the Hippocrates quote "everything in excess is opposed by nature."

Association between TLR2 and TLR4 Gene Polymorphisms and the Susceptibility to Inflammatory Bowel Disease: A Meta-Analysis

Background

The associations between toll-like receptor 2 (TLR2) and toll-like receptor 4(TLR4) polymorphisms and inflammatory bowel disease (IBD) susceptibility remain controversial. A meta-analysis was performed to assess these associations.

Methods

A systematic search was performed to identify all relevant studies relating TLR2 and TLR4 polymorphisms and IBD susceptibility. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Subgroup analyses were performed by ethnicity and publication quality.

Results

Thirty-eight eligible studies, assessing 10970 cases and 7061 controls were included. No TLR2 Arg677Trp polymorphism was found. No significant association was observed between TLR2 Arg753Gln polymorphism and Crohn’s disease (CD) or ulcerative colitis (UC) in all genetic models. Interestingly, TLR4 Asp299Gly polymorphism was significantly associated with increased risk of CD and UC in all genetic models, except for the additive one in CD. In addition, a statistically significant association between TLR4 Asp299Gly polymorphism and IBD was observed among high quality studies evaluating Caucasians, but not Asians. Associations between TLR4 Thr399Ile polymorphisms and CD risk were found only in the allele and dominant models. The TLR4 Thr399Ile polymorphism was associated with UC risk in pooled results as well as subgroup analysis of high quality publications assessing Caucasians, in allele and dominant models.

Conclusions

The meta-analysis provides evidence that TLR2 Arg753Gln is not associated with CD and UC susceptibility in Asians; TLR4 Asp299Gly is associated with CD and UC susceptibility in Caucasians, but not Asians. TLR4 Thr399Ile may be associated with IBD susceptibility in Caucasians only. Additional well-powered studies of Asp299Gly and other TLR4 variants are warranted.

Association of TLR5 gene polymorphisms in ulcerative colitis patients of north India and their role in cytokine homeostasis

Background and Aim

In health, TLR signaling protects the intestinal epithelial barrier and in disease, aberrant TLR signaling stimulates diverse inflammatory responses. Association of TLR polymorphisms is ethnicity dependent but how they impact the complex pathogenesis of IBD is not clearly defined. So we propose to study the status of polymorphisms in TLR family of genes and their effect on cytokines level in UC patients.

Methods

The genotypes of the six loci TLR1-R80T, TLR2-R753Q, TLR3-S258G, TLR5-R392X, TLR5-N592S and TLR6-S249P were determined in 350 controls and 328 UC patients by PCR-RFLP and sequencing. Cytokine levels were measured by ELISA in blood plasma samples. Data were analyzed statistically by SPSS software.

Results

TLR5 variants R392X and N592S showed significant association (p = 0.007, 0.021) with UC patients but TLR 1, 2, 3, 6 variants did not show any association. Unlike other studies carried out in different ethnic groups, TLR 6 (S249P) SNP was universally present in our population irrespective of disease. Genotype-phenotype correlation analysis revealed that the patients having combination of multiple SNPs both in TLR5 and TLR4 gene suffered from severe disease condition and diagnosed at an early age. The level of TNFα (p = 0.004), IL-6 (p = 0.0001) and IFNγ (p = 0.006) significantly increased in patients as compared to controls having wild genotypes for the studied SNPs. However, there was decreased level of TNFα (p = 0.014), IL-6 (p = 0.028) and IFNγ (p = 0.001) in patients carrying TLR5-R392X variant as compared to wild type patients. Patients carrying two simultaneous SNPs D299G in TLR4 gene and N592S in TLR5 gene showed significant decrease in the levels of TNFα (p = 0.011) and IFNγ (p = 0.016).

Conclusion

Polymorphisms in TLR 5 genes were significantly associated with the UC in North Indian population. The cytokine level was significantly modulated in patients with different genotypes of TLR4 and TLR5 SNPs.

Toll-like receptor 4 Asp299Gly and Thr399Ile polymorphisms: New data and a meta-analysis

Background

The pathogenesis of inflammatory bowel disease (IBD) involves interactions between the host genetic susceptibility, intestinal microflora and mucosal immune responses through the pattern recognition receptor. Polymorphisms in toll-like receptor 4 (TLR4) induce an aberrant immune response to indigenous intestinal flora, which might favor IBD development. In this study, we aimed to determine whether TLR4 gene was associated with Crohn’s disease (CD) and ulcerative colitis (UC) among Moroccan patients, and evaluated its correlation with clinical manifestation of the disease.

Methods

The study population comprised 117 patients with IBD and 112 healthy unrelated blood donors. TLR4 polymorphisms: Asp299Gly and Thr399Ile were genotyped by polymerase chain reaction-restriction fragment length polymorphism. PCR products were cleaved with Nco I for the Asp299Gly polymorphism and Hinf I for the Thr399Ile polymorphism. Meta-analysis was performed to test the association of 299Gly and 399Ileu carriage with CD, UC and the overall IBD risk.

Results

Our study revealed that the frequency of Asp299Gly and Thr399Ile did not differ significantly between patients and controls in the Moroccan population. However, meta-analysis demonstrated significantly higher frequencies of both Asp299Gly and Thr399Ile SNPs in IBD and CD and for 399Ileu carriage in UC patients.

Conclusion

The meta-analysis provides evidence that TLR4 polymorphisms confer a significant increased risk for the overall IBD development.

NOD2 gene mutations in ulcerative colitis: useless or misunderstood?

PURPOSE

NOD2 mutations have been linked to an increased risk of Crohn's disease and to some of its phenotypes. The association between NOD2 mutations and susceptibility to ulcerative colitis (UC) remains somewhat controversial and potential correlations between these mutations and UC phenotype have not been studied.

AIM

To assess whether NOD2 mutations are a risk factor for UC in Portugal and if there are any genotype-phenotype correlations in these patients.

METHODS

The three main NOD2 mutations were searched in 200 patients with UC and in 202 healthy controls.

RESULTS

NOD2 mutations were present in 28 patients with UC (14.0 %) and in 27 controls (13.4 %) (p = 0.853). Mutation carriers were more likely to receive steroids during the first year of disease than non-carriers (54.2 % vs. 29.6 %, p = 0.018) and among these patients the need for intravenous administration was more frequent in those with the R702W polymorphism (90.0 % vs. 45.5 %, p = 0.014). In patients with severe colitis admitted for intravenous steroids, a greater proportion of mutation carriers was considered intravenous-steroid refractory and required salvage therapy (90.0 % vs. 38.1 %, p = 0.004). Patients with NOD2 mutation were submitted to colectomy more frequently than non-carriers (17.9 % vs. 4.1 %. p = 0.015). No correlation with the need for immunosuppressants/immunomodulators was found.

CONCLUSIONS

In the Portuguese population, NOD2 mutations do not increase the risk of UC but are associated with a more aggressive course including greater need of steroids in the first year, increased incidence of intravenous-steroid refractoriness and a higher colectomy rate.

Associations of a TLR4 single-nucleotide polymorphism with H. pylori associated gastric diseases in Iranian patients

OBJECTIVE

Helicobacter pylori (H. pylori) is associated with gastric ulcer and gastric adenocarcinoma. Polymorphisms in the host genes coding for toll-like receptors (TLRs) may influence the innate and adaptive immune response to the infection, affecting the susceptibility to H. pylori or the disease outcomes. But the details and association to different polymorphisms and different clinical expressions in patients infected with H. pylori (different clinical expression of H. pylori infection) remain unclear.

METHODS

A case-control study consisting of 195 patients with H. pylori infection and 241 H. pylori uninfection was conducted. Genomic DNA was extracted and genotypes of TLR4Asp299Gly polymorphism were assessed through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Presence of cagA was evaluated using PCR.

RESULTS

TLR4 (Asp299Gly) G and DG alleles frequency in H. pylori infected population was significantly higher in the chronic gastritis group than in the chronic active gastritis group (P=0.021; OR, 2.409; 95% CI, 1.124-5.162). Grade mononuclear (MN) infiltration in H. pylori infected patients with DG genotype of TLR-4 Asp299Gly increased significantly. CagA positivity was more frequently associated with chronic active gastritis (P=0.017, OR=2.26, 95% CI=1.144-4.462) and grade polymorphonucler (PMN) infiltration.

CONCLUSION

TLR-4 Asp299Gly G allele substitution may be modified pattern of immune response in the gastric mucosa of H. pylori infected patients and may be H. pylori infected patients with gastritis have increased risk for the development of chronic gastritis. CagA positivity may be a risk factor for development of gastritis.

NOD2 polymorphisms associated with cancer risk: a meta-analysis

BACKGROUND

Emerging evidence indicated that common polymorphisms of NOD2 might impact individual susceptibility to cancer. However, the results from published studies were inconclusive. The aim of this meta-analysis was to elucidate whether NOD2 polymorphisms were associated with cancer risk.

METHODS

A systematically literature search was performed by using electronic databases including PubMed and Web of Science. ORs and their 95% CI were used to assess the strength of association between NOD2 gene polymorphisms and cancer risks.

RESULTS

Thirty case-control studies were included in this meta-analysis. The pooled analysis indicated that NOD2 rs2066842 C/T polymorphism was not significantly associated with cancer risk; for NOD2 rs2066844 C/T polymorphism, (TT+CT) genotype was associated with increased cancer risk compared with wild-type CC genotype (OR = 1.32, 95% CI = 1.01-1.72, P = 0.041); for NOD2 rs2066845 C/G polymorphism, individuals with (CC+CG) genotype were significantly associated with increased cancer risk compared with GG genotype (OR = 1.32, 95% CI = 1.01-1.72, P = 0.040); for NOD2 rs2066847 (3020insC) polymorphism, carriers of (insC/insC+insC/-) genotype were significantly associated with increased cancer risk compared with -/- carriers (OR = 1.23, 95% CI = 1.10-1.38, P<0.001). In the subgroup analysis of cancer type, (insC/insC+insC/-) genotype was significantly associated with increased risk of colorectal cancer, gastric cancer and MALT lymphoma, breast cancer, lung cancer, laryngeal cancer but not with urogenital cancer, pancreatic cancer, melanoma or non-Hodgkin lymphoma.

CONCLUSION

NOD2 rs2066844 C/T, rs2066845 C/G and rs2066847 (3020insC) polymorphisms might be associated with increased cancer risk. No significant association was observed between NOD2 rs2066842 C/T polymorphism and cancer risk. Further large-scale and well-designed studies are still needed to confirm the results of our meta-analysis.

Should a Toll-like receptor 4 (TLR-4) agonist or antagonist be designed to treat cancer? TLR-4: its expression and effects in the ten most common cancers

Toll-like receptor 4 (TLR-4) is well known for its host innate immunity. Despite the fact that TLR-4 activation confers antitumor responses; emerging evidence suggests that TLR-4 is associated with tumor development and progression. It is now clear that overactivation of TLR-4, through various immune mediators, may cause immune response dysfunction, resulting in tumorigenesis. Different cancers could have different extents of TLR-4 involvement during tumorigenesis or tumor progression. In this review, we focus on infection- and inflammation-related TLR-4 activation in noncancer and cancer cells, as well as on the current evidence about the role of TLR-4 in ten of the most common cancers, viz, head and neck cancer, lung cancer, gastrointestinal cancer, liver cancer, pancreatic cancer, skin cancer, breast cancer, ovarian cancer, cervical cancer, and prostate cancer.

Genetic variants associated with Crohn's disease

Crohn’s disease is an immune-related disorder characterized by inflammation of the gastrointestinal mucosa, which can occur in any area throughout the digestive tract. This life-long disease commonly presents with abdominal pain, diarrhea, vomiting, and weight loss. While the exact etiology of this disease is largely unknown, it is thought to arise from an interaction between microbial, immunological, and environmental factors in a genetically susceptible host, whereby the immune system attacks the intestine as it cross reacts against gut microbial antigens. The study of genetic variants associated with Crohn’s disease has shed light on our understanding of disease pathophysiology. A large number of genetic variants identified in Crohn’s disease are related to genes targeting microbial recognition and bacterial wall sensing, the most common being NOD2/CARD15 gene. This review will discuss the recent advance in our knowledge of genetic variants of this disease and how they influence the disease course and prognosis.

Toll-like receptors and human disease: lessons from single nucleotide polymorphisms

Toll-like receptors (TLRs), a large group of proteins which recognize various pathogen-associated molecular patterns, are critical for the normal function of the innate immune system. Following their discovery many single nucleotide polymorphisms within TLRs and components of their signaling machinery have been discovered and subsequently implicated in a wide range of human diseases including atherosclerosis, sepsis, asthma, and immunodeficiency. This review discusses the effect of genetic variation on TLR function and how they may precipitate disease.

Association between TLR4 and TLR9 gene polymorphisms with development of pulmonary tuberculosis in Zahedan, southeastern Iran

Some evidence suggests that a variety of genetic factors contribute to development of the tuberculosis (TB). TLR4 and TLR9 have been proposed as susceptibility genes for TB. This study was performed in 124 newly diagnosed TB cases and 149 healthy controls in a TB-endemic region of Iran. The TLR4 genes Asp299Gly, Thr399Ile, and TLR9 gene T-1486C polymorphisms were amplified by polymerase chain reaction (PCR) and then detected by PCR-restriction fragment length polymorphism (RFLP). The frequencies of the mutant alleles of TLR4 Arg299Gly, Thr399Ile, and TLR9 T-1486C polymorphisms were 0.8 versus 0.1, 5.6 versus 3, and 28.6 versus 25.2 in patients and controls, respectively, that were not significant. The synergic effect of TI,II/CC genotypes for TLR4 Thr399Ile and TLR9 T-1486C polymorphisms showed increased risk of PTB susceptibility. In conclusion, no significant relation was found between TLR4 and TLR9 polymorphisms alone and PTB. However, synergic effects of TLR4 Thr399Ile and TLR9-1486T/C polymorphisms might increase risk of PTB.

Negative regulation of human mononuclear phagocyte function

At mucosal surfaces, phagocytes such as macrophages coexist with microbial communities; highly controlled regulation of these interactions is essential for immune homeostasis. Pattern-recognition receptors (PRRs) are critical in recognizing and responding to microbial products, and they are subject to negative regulation through various mechanisms, including downregulation of PRR-activating components or induction of inhibitors. Insights into these regulatory mechanisms have been gained through human genetic disease-association studies, in vivo mouse studies utilizing disease models or targeted gene perturbations, and in vitro and ex vivo human cellular studies examining phagocytic cell functions. Although mouse models provide an important approach to study macrophage regulation, human and mouse macrophages exhibit differences, which must be considered when extrapolating mouse findings to human physiology. This review discusses inhibitory regulation of PRR-induced macrophage functions and the consequences of dysregulation of these functions and highlights mechanisms that have a role in intestinal macrophages and in human macrophage studies.

Correlation of Asp299Gly and Thr399Ile polymorphisms in toll-like receptor 4 gene with digestive cancer risk: A meta-analysis

The aim of this meta-analysis was to evaluate the correlation between the Asp299Gly and Thr399Ile polymorphisms in the toll-like receptor 4 (TLR4) gene and the risk of digestive cancer. A comprehensive search in PubMed, Web of Science (ISI), the China National Knowledge Infrastructure (CNKI), the Database of Chinese Scientific and Technical Periodicals (VIP) and the China Biology Medical (CBM) literature databases, including all the studies until May 25 2012, was conducted in order to investigate the abovementioned correlation. Statistical analysis was performed using STATA version 10.1. A total of 12 case-control studies were identified comprising 1,877 cancer patients and 3,181 controls for Asp299Gly polymorphism, and 8 case-control studies with 1,062 cancer patients and 1,867 controls for Thr399Ile polymorphism. Following sensitivity analysis and excluding studies that deviated from the Hardy-Weinberg equilibrium (HWE) in the controls, this meta-analysis demonstrated a significant correlation between the G allele of the Asp299Gly polymorphism and increased risk of gastric cancer in dominant [fixed-effect model (FEM): odds ratio (OR), 1.772; 95% confidence interval (CI), 1.340-2.343] and codominant (FEM: OR, 1.761, CI, 1.347-2.301) models. However, no significant correlation was detected for overall digestive and colorectal cancer. Furthermore, following the sensitivity analysis and exclusion of studies deviating from HWE in controls, no significant effect of the T allele of Thr399Ile polymorphism on overall digestive, gastric and colorectal cancer risk was demonstrated. This study suggests that the G allele of the TLR4 Asp299Gly polymorphism might be correlated with an increased risk of gastric cancer. However, this result needs to be further investigated by future studies.

Difference of interleukin-23 receptor gene haplotype variants in ulcerative colitis compared to Crohn's disease and psoriasis

OBJECTIVE

Polymorphisms of the interleukin-23 receptor (IL23R) gene have been found to play a role in the development of several autoimmune diseases. Our aim was to examine the possible effect of not only simple individual variants, but of haplotypes composed of them.

SUBJECTS

We analysed 263 patients with psoriasis, 199 patients with Crohn's disease (CD), 282 patients with ulcerative colitis (UC), and 253 controls for rs1884444, rs11805303, rs7517847, rs2201841, rs10889677 and rs11209032 variants.

METHODS

The genotypes were determined by using PCR/RFLP assay. Logistic regression analysis was used to compare the genotype distribution of the polymorphisms and haplotypes between the examined autoimmune diseases and healthy controls.

RESULTS

Rs1884444 was found to confer risk for UC and psoriasis, rs10889677 for CD and psoriasis, while rs2201841 and rs7517847 had effect only in CD. Using these SNPs we could study the susceptibility haplotype profiles in these diseases with special attention to UC. Eight different haplotypes could be differentiated. We found that the SNPs exert their susceptibility character in specific haplotype blocks, and the frequency of one haplotype differed significantly in UC compared with both other diseases and also with healthy controls. This haplotype conferred risk for UC, even while it had a somewhat lower frequency in the other diseases than in controls.

CONCLUSIONS

The data presented here serve as evidence for the need of haplotype analysis instead of just single standing SNP analysis when susceptibility is interpreted.

Association between CD14 gene C-260T polymorphism and inflammatory bowel disease: a meta-analysis

Background

The gene encoding CD14 has been proposed as an IBD-susceptibility gene with its polymorphism C-260T being widely evaluated, yet with conflicting results. The aim of this study was to investigate the association between this polymorphism and IBD by conducting a meta-analysis.

Methodology/Principal Findings

Seventeen articles met the inclusion criteria, which included a total of 18 case-control studies, including 1900 ulcerative colitis (UC) cases, 2535 Crohn's disease (CD) cases, and 4004 controls. Data were analyzed using STATA software. Overall, association between C-260T polymorphism and increased UC risk was significant in allelic comparison (odds ratio [OR]  = 1.21, 95% confidence interval [CI]: 1.02–1.43; P = 0.027), homozygote model (OR  = 1.44, 95% CI: 1.03–2.01; P = 0.033), as well as dominant model (OR  = 1.36, 95% CI: 1.06–1.75; P = 0.016). However, there was negative association between this polymorphism and CD risk across all genetic models. Subgroup analyses by ethnicity suggested the risk-conferring profiles of -260T allele and -260 TT genotype with UC in Asians, but not in Caucasians. There was a low probability of publication bias.

Conclusions/Significance

Expanding previous results of individual studies, our findings demonstrated that CD14 gene C-260T polymorphism might be a promising candidate marker in susceptibility to UC, especially in Asians.

Polymorphisms of the CD14 genes are associated with susceptibility to alcoholic liver disease in Greek patients

BACKGROUND

The incidence and severity of alcoholic liver disease (ALD) in chronic drinkers has been found to correlate with some environmental factors and especially with the dose of alcohol consumption, but it is obvious that other parameters clearly contribute to individual alcohol susceptibility. Chronic ethanol exposure leads to continuous endotoxin-mediated Toll-like receptor-4 (TLR-4) and CD14 activation and subsequent cytokine release resulting in chronic inflammation with continued hepatocellular damage. Therefore, genetic studies of polymorphism in TLR-4 and CD14 genes seem to be appropriate in determining genetic susceptibility to ALD. Our aim is to evaluate in a series of Greek drinkers, the possible association of polymorphisms in the TLR-4 and CD14 genes with ALD.

METHODS

In 96 patients with ALD polymorphism of TLR-4 and CD14 genes were studied compared with 104 patients with cirrhosis of other etiology, 100 healthy subjects, and 50 patients with a history of alcohol abuse but without liver disease.

RESULTS

No association between ALD and the presence of the Asp299Gly and Thr399Ile polymorphisms in the TLR-4 gene could be documented in our patients. Regarding the CD14 -159 (C/T) genotypes, TT genotype and T allele were found to be overrepresented in alcoholic patients compared with patients with nonalcohol-induced liver disease and healthy controls. On the other side, when compared patients with ALD and patients with alcohol abuse and no liver disease, TT genotype was found to be significantly less frequent. There is no statistically significant association with the presence of the T allele and the severity of ALD, suggesting that CD14 polymorphism does not influence disease severity in advanced stages of the disease.

CONCLUSIONS

In our series in Greek patients with alcohol abuse and alcoholic cirrhosis, a significant negative association with the CD14 endotoxin receptor gene polymorphism (TT genotype) but not with the TLR-4 gene polymorphism was documented.

CARD15/NOD2, CD14 and toll-like 4 receptor gene polymorphisms in Saudi patients with Crohn's Disease

Crohn’s disease (CD) is a multifactorial disease with a genetic component and an observed association with genes related to the innate immune response. Polymorphisms in the CARD15/NOD2 gene, in addition to functional variants of the toll-like receptor-4 (TLR4) and CD14 genes, have been associated with the development of Crohn’s disease. There is no information about the frequency of these polymorphisms in the Saudi population. We examined the frequency of the three major CARD15/NOD2 risk alleles (Leu1007fsinsC, Arg702Trp, and Gly908Arg) and the TLR4 (Thr399Il) polymorphism as well as a functional polymorphism in the promoter of the CD14–159C/T in 46 Saudi CD patients and 50 matched controls. Genotyping was performed by allele-specific PCR or by restriction fragment length polymorphism (PCR-RFLP) analysis. The mutant genotype frequencies of the Leu1007fsinsC, Arg702Trp and Gly908Arg in the patient group were 6.5, 21.7 and 6.5%, respectively, compared with frequencies of 0, 4 and 2%, respectively, in the control group. There were 15 patients who carried the mutant alleles for all three CARD15/NOD2 variants, Leu1007fsinsC, Arg702Trp and Gly908Arg, while none of the control candidates carried the three alleles. This genetic study provides evidence that the three major CARD15/NOD2 variant alleles and the CD14 –159C/T polymorphism are associated with Crohn’s disease (CD) susceptibility in the Saudi population; however, there is no evidence that the TLR4 (Thr399Il) or CARD15/NOD2 polymorphisms can be considered risk factors for Crohn’s disease.

Polymorphisms of innate immunity receptors in infection by parasites

The innate immune system is the first line of defence against infection by pathogenic bacteria, virus and parasites and is also responsible for initiating an adaptive immune response. In contrast to the receptors of adaptive immunity (TCRs and antibodies) which are generated by gene recombination, receptors of the innate immune system are encoded in the germline and are thus inherited from generation to generation. Although evolutionarily selected, the genes encoding the innate recognition receptors show variations among individuals, and these polymorphisms may have an impact on the ability of an individual to deal with an infection. In recent years, several polymorphisms have been identified in innate recognition receptors, and efforts are being made to determine whether these polymorphisms are associated with a higher or lower susceptibility to infectious diseases. These studies will allow a better understanding of the role of innate receptors in specific diseases and are valuable in the design of preventive or therapeutic interventions to fight the disease. In this review, we summarize studies aimed at determining the influence of polymorphisms in innate recognition receptors on the susceptibility to diseases caused by parasites.

Association between OCTN1/2 gene polymorphisms (1672C-T, 207G-C) and susceptibility of Crohn's disease: a meta-analysis

PURPOSE

Although a number of genetic studies have attempted to link organic cation transporter 1/2 (OCTN1/2) polymorphisms to susceptibility of Crohn's disease (CD), the results were often inconsistent. The present study aimed at investigating the associations.

METHODS

The PubMed, EBSCO, and BIOSIS databases were searched to identify eligible studies which were published in English before April 2011. The association was assessed by odds ratio (OR) with 95% confidence intervals (CI).

RESULTS

A total of 15 case-control studies, containing 4,489 cases/5,351 controls for OCTN1 and 4,474 cases/5,377 controls for OCTN2 were included. Overall, significant associations were found between OCTN1/2 polymorphisms and susceptibility of Crohn's disease for all genetic models. In the subgroup analyses, significant associations were found in the Caucasian population for OCTN1 (TT vs. CC: OR = 1.425, 95% CI 1.247-1.628; TT vs. CT: OR = 1.299, 95% CI 1.149-1.468; dominant model: OR = 1.344, 95% CI 1.197-1.508; and recessive model: OR = 1.179, 95% CI 1.066-1.305) and for OCTN2 (CC vs. GG: OR = 1.309, 95% CI 1.078-1.588; CC vs. CG: OR = 1.200, 95% CI 1.002-1.438; dominant model (OR = 1.231, 95% CI 1.036-1.462; recessive model: OR = 1.148, 95% CI 1.031-1.279). Significant associations were not found in the East Asian population.

CONCLUSIONS

This meta-analysis suggests that OCTN1/2 polymorphisms were associated with susceptibility of CD in the Caucasian population but not in the East Asian population.

Association between toll-like receptors/CD14 gene polymorphisms and inflammatory bowel disease in Korean population

The innate immune response in patients who develop inflammatory bowel disease (IBD) may be abnormal. However, the exact role of Toll-like receptors (TLRs) / CD14 gene in the pathogenesis of IBD has not been fully elucidated. We aimed to investigate the association between polymorphisms of TLR1, 2, 4, 6, and CD14 gene and susceptibility to IBD in Korean population. A total 144 patients of IBD (99 patients with ulcerative colitis, 45 patients with Crohn's disease) and 178 healthy controls were enrolled. Using a PCR-RFLP, we evaluated mutations of TLR1 (Arg80Thr), TLR2 (Arg753Gln and Arg677Trp), TLR4 (Asp299Gly and Thr399Ile), TLR6 (Ser249Pro) genes and the -159 C/T promoter polymorphism of CD14 gene. No TLR polymorphisms were detected in Korean subjects. T allele and TT genotype frequencies of CD14 gene were significantly higher in IBD patients than in healthy controls. In subgroup analysis, T allelic frequency was higher in pancolitis phenotype of ulcerative colitis. In Korean population, the promoter polymorphism at -159 C/T of the CD14 gene is positively associated with IBD, both ulcerative colitis and Crohn's disease.