The influence of genetic polymorphisms in TLR4 and TIRAP, and their expression levels in peripheral blood, on susceptibility to sepsis

Association between innate immunity gene polymorphisms and neonatal sepsis development: a systematic review and meta-analysis

BACKGROUND

The aim of this meta-analysis was to analyze all available data from studies investigating associations between polymorphisms in genes responsible for innate immunity and neonatal sepsis development.

METHODS

A comprehensive literature search, reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-S guidelines, was performed with no language restriction. Studies derived using the PICO (population, intervention, comparison and outcomes) strategy, with data on the genotype distribution for innate immunity gene polymorphisms in newborns with and without sepsis. Data were analyzed using Review Manager. The Cochran-Mantel-Haenszel test was used to calculate odds ratios with 95% confidence intervals. Heterogeneity was tested using the I² index.

RESULTS

From a total of 9428 possibly relevant articles, 33 qualified for inclusion in this systematic review. According to the STrengthening the REporting of Genetic Association Studies, 23 studies were found to be of moderate quality, while 10 were of low quality. The results showed an association of the mannose-binding lectin (MBL) exon 1 genetic polymorphism with the risk of culture-proven sepsis. Toll-like receptor (TLR) 4 rs4986791 genotype distribution suggests its association with the increased risk of culture-proven sepsis. The certainty of evidence per GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) varied from very low to low. Publication bias was not detected.

CONCLUSIONS

Out of the 11 investigated single-nucleotide polymorphisms, this meta-analysis found a possible association between the risk for culture-proven sepsis and MBL exon 1 and TLR4 rs4986791 polymorphisms. There is an evident need for larger well-designed, multicentric observational studies investigating inflammatory gene polymorphisms in neonatal sepsis.

TIRAP Rs8177376, Rs611953, Rs3802814, and Rs8177374 Polymorphisms and Their Association with Cervical Cancer Phenotype and Prognosis

Cervical cancer is one of the most common cancers in women worldwide, which is typically caused by human papillomavirus (HPV). Usually, the toll-like receptor (TLR) signaling pathways eliminate the virus from the organism, but in some cases, persistent infection may develop. Unfortunately, the mechanism of immune tolerance is still unclear. Therefore, this study aimed to analyze TIRAP rs8177376, rs611953, rs3802814, and rs8177374 polymorphisms and to identify their impact on cervical cancer phenotype and prognosis. This study included 172 cervical cancer patients. Genotyping was performed using the PCR-RFLP assay. Univariate and multivariate logistic regression and Cox′s regression models were applied for statistical analysis. The results revealed that older age at the time of diagnosis was statistically linked with the rs8177376 T allele (OR = 2.901, 95% Cl 1.750–4.808, p = 0.000) and the rs611953 G allele (OR = 3.258, 95% Cl 1.917–5.536, p = 0.000). Moreover, the T allele of rs8177376 (OR = 0.424, 95% Cl 0.220–0.816, p = 0.010) was found to be statistically associated with the lower tumor grade. Thus, TIRAP polymorphisms might be employed in the future as potential biomarkers for determining the phenotype and prognosis of cervical cancer.

Sesamin attenuates intestinal injury in sepsis via the HMGB1/TLR4/IL-33 signalling pathway

CONTEXT

Sepsis is currently one of the leading causes of death in intensive care units (ICUs). Sesamin was previously reported to inhibit inflammation. However, no studies have revealed the impact of sesamin on sepsis.

OBJECTIVE

We studied the mechanism underlying the effect of sesamin on the pathophysiology of sepsis through the HMGB1/TLR4/IL-33 signalling pathway.

MATERIALS AND METHODS

Fifty male BALB/c mice (n = 10 per group) were used to establish a caecal ligation and puncture (CLP) mouse model, and given daily injections of sesamin at a low, middle, or high concentration (25, 50, or 100 μM) during the seven-day study period; survival curves were generated by the Kaplan-Meier method. H&E staining and TUNEL staining were performed to assess changes in intestinal morphology intestinal damage in the mouse intestinal epithelium. Molecules related to the HMGB1/TLR4/IL-33 pathway were assessed by RT-qPCR and Western blotting.

RESULTS

We found mice in the sepsis group survived for only 4 days, while those treated with sesamin survived for 6-7 days. In addition, sesamin significantly relieved the increase in the levels of MPO (21%, 33.3%), MDA (40.5% and 31.6%), DAO (1.24-fold and 2.31-fold), and pro-inflammatory cytokines such as TNF-α (75% and 79%) and IL-6 (1-fold and 1.67-fold) 24 and 48 h after sepsis induction and downregulated the expression of HMGB1, TLR4, and IL-33 while upregulating the expression of ZO-1 and occludin.

DISCUSSION AND CONCLUSIONS

Sesamin improved the 7-day survival rate of septic mice, suppressed the inflammatory response in sepsis through the HMGB-1/TLR4/IL-33 signalling pathway, and further alleviated intestinal injury.

Comprehensive Evaluation of Lipopolysaccharide-Induced Changes in Rats Based on Metabolomics

Purpose

Substantial evidence indicates that lipopolysaccharide (LPS) exposure can lead to systemic inflammatory response syndrome (SIRS) and multiple organ failure. Previous metabolomic studies have mainly focused on LPS-induced depression or hepatic and renal effects. However, no comprehensive metabolomics-based analysis of the serum, liver, kidney, hippocampus, and heart following exposure to LPS has been undertaken to date.

Material and Methods

Male Sprague-Dawley rats were randomly allocated to a control and a LPS-treated group (n=8). LPS for 2 weeks (0.5 mg/kg every other day) was given via intraperitoneal injection. Gas chromatography-mass spectrometry (GC-MS) was used for metabolite determination, while multivariate statistical analysis was performed to identify differentially expressed metabolites between the two groups.

Results

Our study revealed that 24, 13, 12, 7, and 12 metabolites were differentially expressed between the LPS treatment group and the control group in the serum, liver, kidney, hippocampus, and heart, respectively. We further identified that these metabolic changes were mainly involved with aminoacyl-tRNA biosynthesis; glutathione metabolism; glyoxylate and dicarboxylate metabolism; glycine, serine, and threonine metabolism; arginine biosynthesis; bile acid biosynthesis; and glycerolipid metabolism.

Conclusion

We have systematically elucidated the metabolic changes underlying LPS-induced SIRS, thereby providing insight into the mechanisms associated with these alterations.

The Single Nucleotide Polymorphism Mal-D96N Mice Provide New Insights into Functionality of Mal in TLR Immune Responses

MyD88 adaptor-like (Mal) protein is the most polymorphic of the four key adaptor proteins involved in TLR signaling. TLRs play a critical role in the recognition and immune response to pathogens through activation of the prototypic inflammatory transcription factor NF-κB. The study of single nucleotide polymorphisms in TLRs, adaptors, and signaling mediators has provided key insights into the function of the corresponding genes but also into the susceptibility to infectious diseases in humans. In this study, we have analyzed the immune response of mice carrying the human Mal-D96N genetic variation that has previously been proposed to confer protection against septic shock. We have found that Mal-D96N macrophages display reduced cytokine expression in response to TLR4 and TLR2 ligand challenge. Mal-D96N macrophages also display reduced MAPK activation, NF-κB transactivation, and delayed NF-κB nuclear translocation, presumably via delayed kinetics of Mal interaction with MyD88 following LPS stimulation. Importantly, Mal-D96N genetic variation confers a physiological protective phenotype to in vivo models of LPS-, Escherichia coli-, and influenza A virus-induced hyperinflammatory disease in a gene dosage-dependent manner. Together, these results highlight the critical role Mal plays in regulating optimal TLR-induced inflammatory signaling pathways and suggest the potential therapeutic advantages of targeting the Mal D96 signaling nexus.

Long non‑coding RNA DILC is involved in sepsis by modulating the signaling pathway of the interleukin‑6/signal transducer and activator of transcription 3/Toll‑like receptor 4 axis

Sepsis is characterized by systemic inflammatory responses. In the present study, the role of deleted in liver cancer 1 (DILC), interleukin (IL)‑6, signal transducer and activator of transcription 3 (STAT3), and Toll‑like receptor 4 (TLR4) in the pathogenesis of sepsis was investigated. Reverse transcription‑quantitative polymerase chain reaction analysis and western blotting were performed to evaluate the effects of lipopolysaccharide (LPS) on the expression of DILC, IL‑6, STAT3, and TLR4, in addition to the effects of DILC and IL‑6 on the synthesis of tumor necrosis factor (TNF‑α), chemokine ligand 5 (CCL5), E‑selectin and C‑X‑C motif chemokine receptor 1 (CXCR1). In addition, the regulatory association between DILC, IL‑6, STAT3 and TLR4 was investigated. LPS reduced the expression level of DILC, and enhanced the expression of IL‑6, STAT3 and TLR4. DILC directly and negatively regulated the synthesis of IL‑6, as demonstrated by the markedly decreased luciferase activity in cells transfected with a wild‑type DILC plasmid. On the other hand, compared with the scramble control, DILC and IL‑6 small interfering (si)RNAs significantly suppressed the expression of IL‑6, STAT3 and TLR4. In addition, DILC siRNA enhanced the expression of IL‑6, STAT3 and TLR4, whereas the expression levels of TNF‑α, CCL5, E‑selectin and CXCR1 in LPS‑treated THP‑1 cells were downregulated following transfection with DILC and IL‑6 siRNAs. In patients with sepsis, DILC expression was inhibited, although the expression levels of IL‑6, STAT3 and TLR4 were upregulated. In addition, the expression levels of TNF‑α, CCL5, E‑selectin and CXCR1 in patients with sepsis were higher compared with normal subjects. Therefore, DILC may mediate the crosstalk between the cascades of IL‑6/STAT3 and TNF‑α signaling, indicating that DILC may act as a prognostic biomarker of sepsis, and may serve as a potential therapeutic target for the treatment of sepsis.

Protective Effect of Baicalin Against TLR4-mediated UVA-induced Skin Inflammation

UVA irradiation is known to cause photoaging via production of reactive oxygen species (ROS) and activation of inflammatory processes. Previously, we have demonstrated that baicalin, a plant-derived flavonoid possessing both antioxidant and anti-inflammatory activity, protects mouse keratinocytes against damage from UVB irradiation. However, the role of baicalin in vivo has not been well studied, particularly in the setting of UVA irradiation. To explore the protective effects and mechanisms of baicalin treatment in mice after UVA irradiation, mice were exposed to acute and chronic doses of UVA irradiation with or without baicalin or vehicle. Skin samples were collected for histological staining, RNA isolation, flow cytometry and protein extraction. Our results demonstrate the protective effect of baicalin against UVA-induced oxidative damage and inflammation in mouse skin. These effects are likely mediated via the TLR4 pathway, which may serve as a target for photochemoprevention against skin inflammation.

Evaluation of TLR2, TLR4, and TOLLIP polymorphisms for their role in tuberculosis susceptibility

Previous studies indicated that single-nucleotide polymorphisms (SNPs) of genes coding for toll-like receptors (TLRs) and toll-interacting protein (TOLLIP) may be involved in the pathogenesis of pulmonary tuberculosis (PTB). This study was designed to investigate potential associations between the polymorphisms in TLR2, TLR4, and TOLLIP and susceptibility to latent tuberculosis infection (LTBI) or subsequent PTB in a Chinese Han population. A total of 209 PTB and 201 LTBI patients and 204 healthy control subjects (HCS) were enrolled in our study. We performed a logistic regression including sex and age as covariates to test the effect of genotype. Genotyping was conducted using the improved multiplex ligase detection reaction (iMLDR). Eleven markers in TLR2, TLR4, and TOLLIP were assessed. No significant association between polymorphisms of TLR2 and TLR4 with PTB or LTBI was detected. For TOLLIP, rs5743899 (p = 0.005, OR = 1.83, 95% CI: 1.20-2.80) CC genotype were risk factors for PTB progression. Moreover, rs5743867 under addictive (p = 0.005, OR = 1.54, 95% CI: 1.14-2.07) and recessive model (p = 0.004, OR = 1.86, 95% CI: 1.22-2.83) were also risk factors for PTB susceptibility. Our results indicate that polymorphisms in TOLLIP affected the risk of PTB disease.

Gas chromatography-mass spectrometry metabolomic study of lipopolysaccharides toxicity on rat basophilic leukemia cells

Lipopolysaccharide (LPS) can lead to uncontrollable cytokine production, fatal sepsis syndrome and depression/multiple organ failure, as pathophysiologic demonstration. Various toxic effects of LPS have been extensively reported, mainly on the toxicity of LPS in cellular level, macrophages or tumor cells, etc. This work aimed on the impact of LPS on mast cell metabolism, which focused on LPS-induced cellular metabolic profiles. Gas chromatography-mass spectrometry (GC-MS) based metabolomics strategy was implemented for the endo-metabolites detection in rat basophilic leukemia (RBL-2H3) cells, treated with 10 μg/mL LPS for 24 h, along with multiple time-dose tests of cells viability/apoptosis. Significantly changes metabolites were mainly involved the metabolism of glycine, serine, threonine and the biosynthesis of phenylalanine, tyrosine, tryptophan and pentose phosphate pathway. The endo-metabolism results illustrated that LPS treatment led to downregulation of glycine, serine and threonine metabolism besides pentose phosphate pathway in RBL-2H3 cells. This novel insight into LPS cellular metabolism, provides some heuristic guidance for elucidating the underlying mechanism of LPS-mediated disease.

Time-resolved metabolomics analysis of individual differences during the early stage of lipopolysaccharide-treated rats

Lipopolysaccharide (LPS) can lead to uncontrollable cytokine production and eventually cause fatal sepsis syndrome. Individual toxicity difference of LPS has been widely reported. In our study we observed that two thirds of the rats (24/36) died at a given dose of LPS, while the rest (12/36) survived. Tracking the dynamic metabolic change in survival and non-survival rats in the early stage may reveal new system information to understand the inter-individual variation in response to LPS. As the time-resolved datasets are very complex and no single method can elucidate the problem clearly and comprehensively, the static and dynamic metabolomics methods were employed in combination as cross-validation. Intriguingly, some common results have been observed. Lipids were the main different metabolites between survival and non-survival rats in pre-dose serum and in the early stage of infection with LPS. The LPS treatment led to S-adenosly-methionine and total cysteine individual difference in early stage, and subsequent significant perturbations in energy metabolism and oxidative stress. Furthermore, cytokine profiles were analyzed to identify potential biological associations between cytokines and specific metabolites. Our collective findings may provide some heuristic guidance for elucidating the underlying mechanism of individual difference in LPS-mediated disease.