G2848A and T-1237C polymorphisms of theTLR9gene and susceptibility to inflammatory bowel disease in patients from southern Brazil

Impact of TLR7 and TLR9 polymorphisms on susceptibility to placental infections and pregnancy complications

This study evaluated the impact of the TLR7 Gln11Leu (rs179008) and TLR9 -1237 T/C (rs5743836) single nucleotide polymorphisms (SNPs) on susceptibility to placental infections and pregnancy complications in 455 Brazilian women. Demographic, socioeconomic, gynecological, and clinical characteristics of the women were collected. Placental tissues were sampled from pregnant women and human and viral DNA was extracted. Human alphaherpesvirus 1 (Herpes simplex virus type 1, HSV-1), Human alphaherpesvirus 2 (Herpes simplex virus type 2, HSV-2) and Human betaherpesvirus 5 (Human cytomegalovirus, HCMV) were detected by nested PCR. TLR9 and TLR7 SNPs were genotyped by PCR amplification of bi-directional specific alleles (Bi-PASA) and restriction fragment length polymorphism (RFLP), respectively. Infections at the time of birth were detected in 45.71 % of women. The presence of the TT genotype (recessive model) of the TLR7 SNP was associated with increased susceptibility to HSV-1 infection (O.R. = 2.23, p = 0.05). The presence of the C allele of the TLR9 SNP, in heterozygosis or homozygosis (dominant model), decreased the infection risk by HCMV (O.R. = 0.31, p-mod<0.05). The TT genotype (recessive model) of the TLR7 SNP was significantly associated (p < 0.05) with increased occurrence of pre-treated hypertension. The codominant model of the TLR9 SNP was significantly associated (p < 0.05) with reduced risk of hospitalization during pregnancy. In combination, the AA/CT (TLR7-TLR9) genotypes significantly decreased the risk of placental infection by HSV-1 and/or HSV-2 (O.R. = 0.47, p = 0.02), the susceptibility to all infectious agents considered in combination (O.R. = 0.4, p = 0.00), and the need of hospitalization (O.R. = 0.48, p = 0.02). In conclusion, TLR7 and TLR9 SNPs are potential modulating factors for the risk of placental infections and pregnancy complications.

Transcriptional modulation of pattern recognition receptors in chronic colitis in mice is accompanied with Th1 and Th17 response

Pattern recognition receptors (PRRs) may contribute to inflammatory bowel diseases (IBD) development due to their microbial-sensing ability and the unique microenvironment in the inflamed gut. In this study, the PRR mRNA expression profile together with T cell-associated factors in the colon was examined using a chronic colitis mice model. 8–12 week old C57BL/6 mice were exposed to multiple dextran sodium sulfate (DSS) treatments interspersed with a rest period to mimic the course of chronic colitis. The clinical features and histological data were collected. The mRNA expressions of colonic PRRs, T cell-associated components were measured. Finally, the colons were scored for Foxp3+ cells. During chronic colitis, the histological data, but not the clinical manifestations demonstrated characteristic inflammatory symptoms in the distal colon. In contrast to acute colitis, the expression of all Toll-like receptors (Tlrs), except Tlr5 and Tlr9, was unaffected after repeated DSS treatments. The expression of Nod1 was decreased, while Nod2 increased. After third DSS treatment, only the expressions of Tlr3 and Tlr4 were significantly enhanced. Unlike other PRRs, decreased Tlr5 and increased Tlr9 mRNA expression persisted during the chronic colitis period. As the colitis progress, only the mRNA expression of Ifnγ and Il17 staid increased during chronic colitis, while the acute colitis-associated increase of Il23, and Il10 and Il12 was abolished. Finally, increased histological score of Foxp3+ cell in colon was found during the chronic colitis period. This study provides an expression pattern of PRRs during chronic colitis that is accompanied by a Th1- and Th17 cell-mediated immune response.

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This study provides an extensive survey of PRRs in the colon during chronic DSS-induced colitis.

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Chronic DSS colitis upregulates the mRNA expression of Tlr3, Tlr4, Tlr9 and Nod2.

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As the DSS colitis progresses to a chronic status the expression of Tlr5 decreases.

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The chronic DSS colitis results in a (progressive) increase of Th1 and Th17 cells.

Association between Toll-Like Receptor 9-1237T/C Polymorphism and the Susceptibility of Inflammatory Bowel Diseases: A Meta-Analysis

PURPOSE

The -1237T/C polymorphism of the Toll-like receptor 9 (TLR9) gene has been implicated in the susceptibility of inflammatory bowel diseases (IBDs), but the results remain conflicting. We further investigated this association via meta-analysis.

MATERIALS AND METHODS

Multiple electronic databases were extensively searched until February, 2015. The strength of association was evaluated by calculating the pooled odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

A total of 2987 cases and 2388 controls from eight studies were analyzed. Overall, association was found between TLR9 -1237T/C polymorphism and the risk of IBDs when all the studies were pooled (recessive model, OR: 1.59, 95% CI: 1.02-2.47, p=0.04; homozygote comparison, OR: 1.62, 95% CI: 1.04-2.52, p=0.03; allele model, OR: 1.13, 95% CI: 1.00-1.27, p=0.05). Stratification by ethnicity indicated an association between TLR9 -1237T/C polymorphism and IBDs risk in Caucasians (recessive model, OR: 1.59, 95% CI: 1.02-2.47, p=0.04; homozygote comparison, OR: 1.62, 95% CI: 1.04-2.52, p=0.03; allele model, OR: 1.12, 95% CI: 1.00-1.27, p=0.05). When stratified by disease type, significant correlation were only found in the Crohn's disease subgroup (recessive model, OR: 1.69, 95% CI: 1.05-2.73, p=0.03; homozygote model, OR: 1.74, 95% CI: 1.07-2.82, p=0.02; allele model, OR: 1.15, 95% CI: 1.01-1.32, p=0.04).

CONCLUSION

The present study suggested that the TLR9 -1237T/C polymorphism might act as a risk factor in the development of IBDs, particularly in Caucasians.