Association of TLR and TREM-1 gene polymorphisms with atherosclerosis severity in a Russian population

Influence of trem-1 gene polymorphisms on cytokine levels during malaria by Plasmodium vivax in a frontier area of the Brazilian Amazon

BACKGROUND

The immunopathology during malaria depends on the level of inflammatory response generated. In this scenario, the TREM-1 has been associated with the severity of infectious diseases and could play an important role in the inflammatory course of malaria. We aimed to describe the allelic and genotypic frequency of four polymorphisms in the trem-1 gene in Plasmodium vivax-infected patients and to verify the association of these polymorphisms with clinical and immunological factors in a frontier area of the Brazilian Amazon.

METHODS

We included 76 individuals infected with P. vivax and 144 healthy controls living in the municipality of Oiapoque, Amapá, Brazil. The levels of TNF-α, IL-10, IL-2, IL-4, IL-5, and IFN-γ were measured by flow cytometry, while IL-6, sTREM-1, and antibodies against PvMSP-119 were evaluated by ELISA. The SNPs were genotyped by qPCR technique. Polymorphisms analysis, allelic and genotype, frequencies, and HWE calculation were determined by x2 test in R Software. The association between the parasitemia, gametocytes, antibodies, cytokines, and sTREM-1 with the genotypes of malaria and control groups was performed using the Kruskal-Wallis test, these analyzes were conducted in SPSS Software, at 5% significance level.

RESULTS

All SNPs were successfully genotyped. Allelic and genotypic distribution was in Hardy-Weinberg Equilibrium. Furthermore, several associations were identified between malaria and control groups, with increased levels of IL-5, IL-6, IL-10, TNF-α, and IFN-γ in the infected individuals with rs6910730A, rs2234237T, rs2234246T, rs4711668C alleles compared to the homozygous wild-type and heterozygous genotypes of the controls (p-value < 0.05). No association was found for these SNPs and the levels of IL-2, and sTREM-1.

CONCLUSIONS

The SNPs on the trem-1 gene are associated with the effector molecules of the innate immunity and may contribute to the identification and effective participation of trem-1 in the modulation of the immune response. This association may be essential for the establishment of immunization strategies against malaria.

Impact of TREM1 Variants on the Risk and Prognosis of Glioma in the Chinese Han Population

Background

Glioma is the main pathological subtype of brain tumors with high mortality.

Objective

This study aimed to elucidate the correlation between TREM1 variants and glioma risk in the Chinese Han population.

Methods

Genotyping of six variants of TREM1 was completed by Agena MassARRAY platform in 1061 subjects (503 controls and 558 glioma patients). The relationship between TREM1 polymorphisms and glioma risk was calculated using the logistic regression model, with odds ratio (OR) and 95% confidence intervals (CIs). A multifactor dimensionality reduction (MDR) method was performed to assess SNP-SNP interactions to predict glioma risk.

Results

In this research, overall analysis illustrated an association between TREM1 rs9369269 and an increased risk of glioma. Rs9369269 was also related to the risk of glioma in patients aged ≤40 years and females. Subjects with rs9369269 AC genotype were likely to obtain glioma compared to people with CC genotype (patients with astroglioma vs healthy people). Compared to TT genotype carriers, carriers with AT genotype of rs1351835 were significantly associated with overall survival (OS).

Conclusion

Taken together, the study identified the association between TREM1 variants and glioma risk and TREM1 variants were significantly associated with the prognosis of glioma. In the future, larger samples are needed to verify the results.

Role of intergenic interactions between cytokine and Toll-like receptor genes in the etiology of congenital heart defects

The incidence of congenital heart defects (CHDs) reaches 1% of all newborns. Of particular importance is the group of heart defects without a family history and chromosomal disorders, which makes up>80% of all CHDs. These heart defects can be designated as sporadic CHDs, and their etiology and pathogenesis continue to be studied.

Aim. To study the association of cytokine and Toll-like receptor (TLR) genes with CHDs in children.

Material and methods. We examined 188 children with sporadic (without family history) CHDs (main group) and 103 healthy children without CHDs (control group). Genotyping was performed by real-time polymerase chain reaction (PCR).

Results. Sporadic CHDs, in general, and septal CHDs, in particular, are formed on similar intergenic associations that determine the dysregulation of the proliferation and differentiation of progenitor cells of the cardiovascular system. Probably, one of the molecular mechanisms for sporadic septal CHDs may be the inefficiency of intracellular signaling pathways for Nuclear Factor kappa B (NF-κB) due to the primary deficiency of membrane heterodimers TLR1/TLR6, TLR2/TLR6, and TLR1/TLR2.

Conclusion. Data on altered proinflammatory potential in the group of sporadic septal CHDs should be taken into account in the postnatal period when conducting cardiac surgery.

Plasma and genetic determinants of soluble TREM-1 and major adverse cardiovascular events in a prospective cohort of acute myocardial infarction patients. Results from the FAST-MI 2010 study

INTRODUCTION

Triggering receptor expressing on myeloid cells (TREM)-1 is involved in the pathophysiology of ischemic heart disease. Plasma soluble TREM-1 levels (sTREM-1) has been associated with increased risk of major adverse cardiovascular events (MACE) in acute myocardial infarction (AMI) patients. However, the causative link between TREM-1 and MACE remains unknown and requires further investigation before developing potential therapeutic approaches.

METHODS AND RESULTS

Using the serum and DNA data bank from the prospective, nationwide French registry of Acute ST-elevation and non-ST-elevation Myocardial Infarction (FAST-MI 2010, N = 1293), we studied the association of plasma levels of sTREM-1 with 9 common genetic variants at the TREM1 locus and their relationship with recurrent MACE over a 3-year follow up. Plasma levels of sTREM-1 were associated with an increased risk of MACEs (death, recurrent MI or stroke) (adjusted HR = 1.86, 95%CI = 1.06-3.26 and HR = 1.11, 95%CI = 0.61-2.02 respectively for tertiles 3 and 2 versus tertile 1, P < 0.001). The study of common variants identified two major genetic determinants of sTREM-1 (rs4714449: beta = -0.11, P_add = 7.85 × 10^-5 and rs3804276: beta = 0.18, P_add = 2.65 × 10^-11) with a potential role on maintenance and/or differentiation of hematopoietic stem cells. However, associated variants only explained 4% of sTREM-1 variance (P = 2.74 × 10^-14). Moreover, the rs4714449 variant, individually and in haplotype, was not significantly associated with MACE (HR = 0.61, 95%CI: 0.35-1.05, P = 0.07).

CONCLUSIONS

Despite its relationship with increased risk of death, recurrent MI and stroke, genetic determinants of plasma levels of sTREM-1 were not found to be causal prognostic factors in patients with acute myocardial infarction.

Accuracy of triggering receptor expressed on myeloid cells 1 in diagnosis and prognosis of acute myocardial infarction: a prospective cohort study

Background

Acute myocardial infarction (AMI) is one of the fatal cardiac emergencies. The detection of triggering receptor expressed on myeloid cells 1 (TREM1), a cell surface immunoglobulin that amplifies pro-inflammatory responses, screened by bioinformatics was shown to be significant in diagnosing and predicting the prognosis of AMI.

Methods

GSE66360, GSE61144 and GSE60993 were downloaded from the Gene Expression Omnibus (GEO) database to explore the differentially expressed genes (DEGs) between AMI and control groups using R software. A total of 147 patients in total were prospectively enrolled from October 2018 to June 2019 and divided into two groups, the normal group (n = 35) and the AMI group (n = 112). Plasma was collected from each patient at admission and all patients received 6-month follow-up care.

Results

According to bioinformatic analysis, TREM1 was an important DEG in patients with AMI. Compared with the normal group, TREM1 expression was markedly increased in the AMI group (p < 0.001). TREM1 expression was positively correlated with fasting plasma glucose (FPG), glycosylated hemoglobin (HbAC), and the number of lesion vessels, although it had no correlation with Gensini score. TREM1 expression in the triple-vessels group was significantly higher than that of the single-vessel group (p < 0.05). Multiple linear regression showed that UA and HbAC were two factors influencing TREM1 expression. The ROC curve showed that TREM1 had a diagnostic significance in AMI (p < 0.001), especially in AMI patients without diabetes. Cox regression showed increased TREM1 expression was closely associated with 6-month major adverse cardiac events (MACEs) (p < 0.001).

Conclusions

TREM1 is a potentially significant biomarker for the diagnosis of AMI and may be closely associated with the severity of coronary lesions and diabetes. TREM1 may also be helpful in predicting the 6-month MACEs after AMI.

TREM1 rs2234237 (Thr25Ser) Polymorphism in Patients with Cutaneous Leishmaniasis Caused by Leishmania guyanensis: A Case-Control Study in the State of Amazonas, Brazil

Background: Leishmaniasis is an infectious disease caused by Leishmania parasites. A Th1 immune response is necessary in the acute phase to control the pathogen. The triggering receptor expressed on myeloid cells (TREM)-1 is a potent amplifier of inflammation. Our aim is to identify whether the TREM1 variant rs2234237 A/T (Thr25Ser) is associated with the disease development of cutaneous leishmaniasis (CL) in Leishmania guyanensis-infected individuals. The effects of the rs2234237 genotypes on plasma cytokines IL-1β, IL-6, IL-8, IL-10, MCP-1 and TNF-α are also investigated. Methods: 838 patients with CL and 818 healthy controls (HCs) living in the same endemic areas were genotyped by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism. Plasma cytokines were assayed in 400 patients with CL and 400 HCs using the BioPlex assay. Results: The genotypes’ and alleles’ frequencies were similar in both patients with CL (AA = 618, 74%; AT = 202, 24%; TT = 18, 2%) and in HCs (AA = 580, 71%; AT = 220, 27%; TT = 18, 2%). Rs2234237 showed a modest effect on plasma IL-10 that disappeared when correction of the p-value was applied. Plasma IL-10 by rs2234237 genotypes were (mean ± SEM; AA = 2.91 pg/mL ± 0.14; AT = 2.35 pg/mL ± 0.12; TT = 3.14 pg/mL ± 0.56; p = 0.05). Conclusion: The TREM1 rs2234237 (Thr25Ser) seems to have no influence on the susceptibility or resistance to L. guyanensis infections.

Elevated Plasma Soluble Triggering Receptor Expressed on Myeloid Cells-1 Level in Patients with Acute Coronary Syndrome (ACS): A Biomarker of Disease Severity and Outcome

Background and Aims

Plasma levels of soluble triggering receptor expressed on myeloid cells (sTREM-1) reflect innate immune cell activation. We sought to evaluate sTREM-1 levels in patients with acute coronary syndrome (ACS) and their predictive value for disease severity and outcome.

Methods

Plasma sTREM-1 levels were prospectively measured by ELISA in 121 consecutive patients with new-onset (≤24 h) chest pain at arrival to the emergency department (ED) and 73 healthy controls. Secondary endpoints were the association of plasma levels of sTREM-1 with day 30 and month 6 major adverse cardiovascular events (MACE) defined as death, ACS, stroke, and need for coronary revascularization, as well as with CAD severity. The primary endpoint of the study was the association of plasma sTREM-1 level at the time of admission to the ED with a diagnosis of ACS at day 30.

Results

Fifty-nine patients (48.7%) were diagnosed with ACS and 62 (51.3%) with nonspecific chest pain (NSCP). Median plasma sTREM-1 level at admission was significantly higher in the ACS group than the NSCP group and the control group (539.4 ± 330.3 pg/ml vs. 432.5 ± 196.4 pg/ml vs. 230.1 ± 85.5 pg/ml, respectively; P < 0.001) and positively correlated with the number of stenosed/occluded coronary arteries on angiography (P < 0.001). On logistic regression analysis, higher sTREM-1 levels predicted definite ACS vs. NSCP determined on day 30 (OR 1.29, 95% CI 1.07-1.54, P = 0.01) as well as with recurrent ACS (P = 0.04) and stroke (P = 0.02) at 6 months.

Conclusions

Plasma sTREM-1 levels are significantly elevated in patients with ACS and might serve as a biomarker differentiating ACS from NSCP in the ED as well as an inflammatory biomarker for coronary artery disease severity and outcome.

Association of chronic inflammation and accelerated atherosclerosis among an indigenous black population with chronic kidney disease

Introduction

Inflammation plays a major role in the development of atherosclerosis and cardiovascular morbidity and mortality in chronic kidney disease (CKD) patients. Toll-like receptor-4 (TLR4) is a major receptor for lipopolysaccharides (endotoxin) and other ligands involved in the pathogenesis of inflammation. We determined whether endotoxin levels and the presence of TLR4 polymorphisms are associated with markers of inflammation and atherosclerosis among South African CKD patients.

Materials and methods

Endotoxin, lipopolysaccharide binding protein (LBP), serum CD14 (sCD14), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1) and carotid intima media thickness (CIMT) were measured in 160 participants (120 CKD patients and 40 controls). Associations between endotoxins and CIMT in the presence of sCD14, IL-8 and MCP-1, were assessed using odds ratios. Participants were screened for the presence of Asp299Gly and Thr399Ile TLR4 polymorphisms, and CIMT and inflammatory markers were compared between subjects with and without TLR4 polymorphisms.

Results

Endotoxin levels correlated with sCD14 (r = 0.441, p<0.001) and MCP-1 (r = 0.388, p<0.001) levels while increased CIMT was associated with MCP-1 (r = 0.448, p<0.001), sCD14 levels (r = 0.476, p<0.001), LBP (r = 0.340, p<0.001), and IL-8 (r = 0.395, p<0.001). Atherosclerosis was associated with endotoxin levels (odds ratio: 4.95; 95% confidence interval: 2.52–9.73; p<0.001), and was predicted by higher serum levels of inflammatory markers. Analysis of patients with TLR4 polymorphisms showed reduced serum levels of inflammatory markers and CIMT values compared with the patients carrying the wild type TLR4 alleles.

Conclusion

The study demonstrated associations between circulating endotoxaemia, systemic inflammation and accelerated atherosclerosis among South African CKD patients, and showed that the atherogenic predictive power of endotoxaemia was significantly increased by the presence of elevated levels of inflammatory markers. Additional findings, which must be confirmed, suggest that TLR4 polymorphisms are associated with low levels of inflammatory markers and CIMT values.

Characterization and strong risk association of TLR2 del -196 to -174 polymorphism and Helicobacter pylori and their influence on mRNA expression in gastric cancer

BACKGROUND

Toll-like receptor-2 (TLR2) is responsible for recognizing Helicobacter pylori (H. pylori) and activating the immune response. Polymorphisms in TLR2 may modulate gastric carcinogenesis.

AIM

To evaluate whether the TLR2 19216T/C (rs3804099) and TLR2 -196 to -174 ins/del (rs111200466) polymorphisms contribute to gastric carcinogenesis in the Brazilian population, and to determine the influence of both polymorphisms and H. pylori infection on TLR2 mRNA expression.

METHODS

DNA was extracted from 854 peripheral blood leukocyte or gastric tissue samples [202 gastric cancer (GC), 269 chronic gastritis (CG), and 383 control/healthy (C)] and genotyped by allele-specific PCR or restriction fragment length polymorphism (RFLP)-PCR. Quantitative polymerase chain reaction by TaqMan® assay was used to quantify TLR2 mRNA levels in fresh gastric tissues (48 GC, 36 CG, and 14 C).

RESULTS

Regarding the TLR2 -196 to -174 polymorphism, the ins/del and del/del genotypes were associated with a higher risk of GC by comparison with the C in all of the analyzed inheritance models (codominant, dominant, recessive, overdominant and log-additive; P < 0.0001). Similarly, an increased risk was observed when comparing the GC and CG groups [codominant (P < 0.0001), dominant (P < 0.0001), recessive (P = 0.0260), overdominant (P < 0.0001) and log-additive (P < 0.0001)]. In contrast, TLR2 19216T/C was associated with a protective effect in the GC group compared to the C group [dominant (P = 0.0420) and log-additive (P = 0.0300)]. Regarding the association of polymorphisms with H. pylori infection, individuals infected with H. pylori and harboring the TLR2 -196 to -174 ins/del polymorphism had an increased risk of gastric carcinogenesis [codominant (P = 0.0120), dominant (P = 0.0051), overdominant (P = 0.0240) and log-additive (P = 0.0030)], while TLR2 19216T/C was associated with a protective effect [codominant (P = 0.0039), dominant (P < 0.0001), overdominant (P = 0.0097) and log-additive (P = 0.0021)]. TLR2 mRNA levels were significantly increased in the GC group (median RQ = 6.95) compared to the CG group (RQ = 0.84, P < 0.0001) and to the normal mucosa group (RQ = 1.0). In addition, both H. pylori infection (P < 0.0001) and the presence of the polymorphic TLR2 -196 to -174del (P = 0.0010) and TLR2 19216 C (P = 0.0004) alleles influenced TLR2 mRNA expression.

CONCLUSION

The TLR2 -196 to -174 ins/del and TLR2 19216 T/C polymorphisms are strongly associated with GC. TLR2 mRNA expression levels are upregulated in neoplastic tissues and influenced by both the presence of H. pylori and variant genotypes.

Protective effect of rivaroxaban on arteriosclerosis obliterans in rats through modulation of the toll-like receptor 4/NF-κB signaling pathway

The aim of the present study was to explore the pharmacological role of rivaroxaban in rats with arteriosclerosis obliterans (ASO) and the potential mechanism of its action. A total of 60 adult male Sprague Dawley (weighing 210–250 g) were randomly assigned into either the sham group, model group or Riv group. Rats in the sham group were fed a normal diet, whereas those in model group and Riv group were fed a high-fat diet for 8 weeks. After establishment of the ASO model, rats in the Riv group were intragastrically administered 10 mg/kg rivaroxaban, whereas those in the sham group and the model group were administrated with the same volume of 0.9% saline for 4 weeks. At the end of animal procedures, a blood sample and the femoral artery of the rats were harvested. The results of the present study revealed that rats in the model group presented with an irregularly narrowed femoral artery lumen, disordered endothelial cells, internal elastic plates and smooth muscle cells. By comparison, the arterial wall structure and stenosis of the femoral artery of rats in Riv group recovered and all the pathological changes were alleviated after rivaroxaban treatment. Levels of total cholesterol, triglycerides and low-density lipoproteins decreased, whereas the level of high-density lipoproteins increased in the Riv group compared with the model group. Rivaroxaban treatment significantly reduced serum levels of interleukin-1, tumor necrosis factor-α and monocyte chemoattractant protein-1 (MCP-1), and increased the serum level of transforming growth factor-β (TGF-β). Rats in the Riv group had reduced expression of toll-like receptor 4 (TLR4), NF-κB and MCP-1, and increased expression of TGF-β in femoral artery tissues compared with the model group. Therefore rivaroxaban may have exerted its anti-atherosclerotic effects by regulating the expression of genes in the TLR4/NF-κB signaling pathway and the activation of the downstream molecules.

Genetic variations of TLRs and their association with HPV/EBV, co-infection along with nicotine exposure in the development of premalignant/malignant lesions of the oral cavity in Indian population

BACKGROUND

Despite being most preventable malignancies associated with smoked and smokeless tobacco products, squamous cell carcinoma of oral cavity is one of the most common malignancy in India. The aim of the present study was to evaluate the role of TLRs in oral pre-cancerous, cancerous cases and their genotypic correlation with HPV/EBV, co-infection & lifestyle habits in Indian population.

METHODS

The present study was conducted on 300 subjects (100 OSCC, 50 pre-cancer & 150 controls). The amplification of TLRs gene and HPV/EBV co-infection was assessed by Nested PCR, PCR-RFLP and further confirmation by direct sequencing.

RESULTS

The TLR 9(-1486 T/C), revealed that the TT vs. CT + CC genotype had a ˜5-fold increased risk for the development of pre-cancerous lesions as compared to controls (p = 0.0001). Further analysis showed that the risk of cancer was extremely pronounced in HPV/EBV, co-infection (p = 0.0141), implicating the possible interaction between TLR 9(-1486T/C) genotype and HPV infection in increasing cancer/pre-cancer risk. The 'G' allele of TLR 4(+896A/G) was also a higher risk of developing pre-cancerous lesions with 4.5 fold and statistically significant (p = 0.0001). The genotypic association of TLR 9(-1486T/C) in OSMF cases showed ˜8 fold increased risk and TLR 4(+896A/G) showed fourteen fold higher risk for leukoplakia (p < 0.0001, OR = 14.000).

CONCLUSION

Genetic polymorphism of TLR 9(-1486 T/C) and TLR 4(+896A/G) may influence the effects of HPV/EBV, co-infection and play the significant role in development of the disease. The significance of these TLRs seemed to be enhanced by tobacco chewing and smoking habits also, which act as an important etiological risk factor for OSCC.

The polymorphism rs4696480 in the TLR2 gene is associated with psoriasis patients in the Turkish population

BACKGROUND

Toll-like receptors (TLRs) have an important role in the host defense. Recent studies demonstrated that TLR polymorphisms might have a role in the pathogenesis of psoriasis vulgaris. The aim of this study was to indicate whether TLR2 rs11938228 and rs4696480 were associated with susceptibility to psoriasis in the Turkish population.

METHODS

This case-control study included 140 psoriasis patients and 250 controls. Genotyping of 2 rs11938228 and rs4696480 SNPs of TLR2 were determined using LightSNiP Kit (Roche Diagnostic, GmBH, Mannheim, Germany).

RESULTS

Our results demonstrated that the TLR2-rs4696480 AA genotype seemed to have a higher risk for psoriasis [crude 95% CI: 1.495-4.514, and p < 0.001, adjusted 95% CI: 1.349-4.292, and p = 0.003] while as TLR2-rs11938228 polymorphism has not shown any significant association with the risk of psoriasis [p > 0.005]. There was no statistically significant difference between the mean age, gender, onset age, and PASI level and genotypes for rs11938228 and rs4696480 polymorphisms (p > 0.05).

CONCLUSIONS

The SNP rs4696480 of TLR2 may have significant effects on the heritability of psoriasis in the Turkish population.

Sirt6-induced autophagy restricted TREM-1-mediated pyroptosis in ox-LDL-treated endothelial cells: relevance to prognostication of patients with acute myocardial infarction

Inflammation mediated by myeloid cells trigger receptors 1 (TREM-1) is important for atherosclerosis development, while sirtuin 6 (Sirt6) levels decrease in atheroscleoritc plaque. Here we demonstrate that oxidatively modified low density lipoprotein (ox-LDL)-treated endothelial cells (ECs) exhibited increased TREM-1-mediated pyroptosis and decreased Sirt6-induced autophagy. We show that high sTREM-1 and low sSirt6 levels were independent predictors of boosted endothelial microparticles (EMPs) on admission, and were associated with increased risk for all-cause mortality and major adverse cardiovascular events (MACE) at median 24 months (interquartile range, 18–26) follow-up in acute myocardial infarction (AMI) patients. Additionally, blockage of Sirt6-induced autophagy led to augmented TREM-1-mediated pyroptosis, whereas Sirt6 overexpression attenuated ECs inflammation and pyroptosis following ox-LDL treatment. Our findings indicate that TREM-1 and in a reversed trend Sirt6 appeared to be markers of endothelial inflammation with potential for use in risk stratification.

Association between Toll-like receptors (TLR) and NOD-like receptor (NLR) polymorphisms and lipid and glucose metabolism

Recent evidences had shown activation of TLR (toll-like receptors) and NLR (nod-like receptors) in response to imbalance in nutrients intake, such as lipid and glucose. The main aim of this study was to investigate possible associations between 11 SNPs in TLR2, TLR4, NLRC4, CARD8 and NEK7 genes and lipid and glucose metabolism. Sample was composed by healthy children and adolescents (n = 158) and adults (n = 115). DNA extraction was obtained by salting-out and sample genotyping by matrix-assisted laser desorption ionization time-of-flight mass spectrometry based system. LDL-cholesterol, HDL-cholesterol, triglycerides, total cholesterol, glucose and insulin were measured by standard automated methods. Means were compared by t-test or Mann-Whitney test. Univariate and multivariate logistic regression were used to verify association between polymorphisms and lipid and glucose markers. Seven polymorphisms in 5 genes were associated with lipid and glucose parameters. For lipid parameters, the following associations were found: higher LDL-C levels and C allele of rs1554973 (TLR4) and G allele of rs6671879 (NEK7); higher HDL-cholesterol levels and A allele of rs13105517 (TLR2); higher total cholesterol and TT genotype of rs3804099 (TLR2) and G allele of rs6671879 (NEK7); higher triglycerides levels and G allele of rs455060 (NLRC4). For glucose parameters associations were found between C allele of rs7258674 (CARD8) and higher glucose levels, and between C allele of rs212704 (NLRC4) and G allele of rs455060 (NLRC4) and insulin levels. These findings indicate a relationship between polymorphisms of TLRs and NLRs genes and markers of lipid and glucose metabolism.

TREM-1; Is It a Pivotal Target for Cardiovascular Diseases?

Cardiovascular diseases (CVDs) are as menacing as ever and still continue to kill adults worldwide, notwithstanding tremendous efforts to decrease their consequent mortality and morbidity. Lately, a growing body of research indicated that inflammation plays a pivotal role in the pathogenesis and complications of CVDs. A receptor of the immunoglobulin superfamily, triggering receptors expressed on myeloid cells-1 (TREM-1) was shown to induce and amplify the inflammation in both acute and chronic disease’ pathogenesis and progression, which hence makes it one of the most important complication factors of CVDs. Thus, studies endeavored to investigate the role played by TREM-1 in CVDs with respect to their etiologies, complications, and possible therapeutics. We examined here, for the first time, the most relevant studies regarding TREM-1 involvement in CVDs. We critically analyzed and summarized our findings and made some suggestions for furtherance of the investigations with the aim to utilize TREM-1 and its pathways for diagnostic, management, and prognosis of CVDs. Overall, TREM-1 was found to be involved in the pathogenesis of acute and chronic cardiovascular conditions, such as acute myocardial infarction (AMI) and atherosclerosis. Although most therapeutic approaches are yet to be elucidated, our present research outcome displays a promising future to utilizing the TREM-1 pathway as a potential target for understanding and managing CVDs.

Prognostic Utility of Soluble TREM-1 in Predicting Mortality and Cardiovascular Events in Patients With Acute Myocardial Infarction

BACKGROUND

Triggering receptor expressed on myeloid cells-1 (TREM-1) is thought to be critical for inflammatory signal amplification and involved in the development of atherosclerosis. TREM-1 is significantly increased in patients with myocardial infarction. The aim of this study was to investigate the association between soluble TREM-1 (sTREM-1) and mortality and cardiovascular events in patients with acute myocardial infarction.

METHODS AND RESULTS

We included 838 consecutive patients with acute myocardial infarction from October 7, 2012 to December 5, 2014. Blood samples were collected from patients with acute myocardial infarction immediately after diagnosis. During follow-up, 88 patients died, and 180 patients reached the combined end points of major adverse cardiovascular event (MACE). Patients with high sTREM-1 (higher than the median) had increased risk of all-cause mortality and MACE compared with those with low sTREM-1 (log-rank test, P<0.001). After adjustment for confounding risk factors by Cox regression analysis, high sTREM-1 remained an independent predictor of all-cause mortality (hazard ratio, 1.978; 95% confidence interval, 1.462-2.675; P<0.001) and MACE (hazard ratio, 2.413; 95% confidence interval, 2.022-2.879; P<0.001). After the addition of sTREM-1 to the reference model, the C-statistic for all-cause mortality increased from 0.86 to 0.89, and the difference was 0.023 (95% confidence interval, 0.0009-0.0477), and the C-statistic for MACE increased from 0.71 to 0.80, and the difference was 0.087 (95% confidence interval, 0.053-0.122). sTREM-1 levels were consistently positively associated with risks of all-cause mortality and MACE in various subpopulations, and there was no significant interaction among prespecified subgroups.

CONCLUSIONS

sTREM-1 was significantly associated with all-cause mortality and MACE, independent of established conventional risk factors in patients with acute myocardial infarction.

Evolving targets for the treatment of atherosclerosis

Atherosclerosis is a progressive disease of large arteries and a leading cause of cardiovascular diseases and stroke. Chronic inflammation, aberrant immune response, and disturbances to key enzymes involved with lipid metabolism are characteristic features of atherosclerosis. Apart from targeting the derangements in lipid metabolism, therapeutic modulation to regulate chronic inflammation and the immune system response may prove to be very promising strategies in the management of atherosclerosis. In recent years, various targets have been studied for the treatment of atherosclerosis. PCSK9, a serine protease, actively targets the LDL-R and causes lysosomal degradation, which leads to excessive accumulation of LDL-C. Regulatory T cells (Tregs) and Triggering Receptor Expressed on Myeloid cells-1 (TREM-1) affects the adaptive and innate immune response, respectively, and thus, therapeutic intervention of either of these targets would directly modulate disease progression. Advanced atherosclerotic lesions are characterized by an accumulation of apoptotic cells. Cluster of differentiation-47 (CD47), an anti-phagocytic known as the "don't eat me" signaling molecule, inhibits efferocytosis, which causes accumulation of cell debris in plaque. ADAMTS and Notch signaling potentially affect the formation of neointima by modulation of extracellular matrix components such as macrophages and vascular smooth muscle cells. This review provides insights on the molecular targets for therapeutic intervention of atherosclerosis, their effect at various stages of atherosclerosis development, and the therapies that have been designed and currently being evaluated in clinical trials.

TREM-1 SNP rs2234246 regulates TREM-1 protein and mRNA levels and is associated with plasma levels of L-selectin

High levels of TREM-1 are associated with cardiovascular and inflammatory diseases risks and the most recent studies have showed that TREM-1 deletion or blockade is associated with up to 60% reduction of the development of atherosclerosis. So far, it is unknown whether the levels of TREM-1 protein are genetically regulated. Moreover, TREM family receptors have been suggested to regulate the cellular adhesion process. The goal of this study was to investigate whether polymorphisms within TREM-1 are regulating the variants of serum TREM-1 levels and the expression levels of their mRNA. Furthermore, we aimed to point out associations between polymorphisms on TREM-1 and blood levels of selectins. Among the 10 SNPs studied, the minor allele T of rs2234246, was associated with increased sTREM-1 in the discovery population (p-value = 0.003), explaining 33% of its variance, and with increased levels of mRNA (p-value = 0.007). The same allele was associated with increased soluble L-selectin levels (p-value = 0.011). The higher levels of sTREM-1 and L-selectin were confirmed in the replication population (p-value = 0.0007 and p-value = 0.018 respectively). We demonstrated for the first time one SNP on TREM-1, affecting its expression levels. These novel results, support the hypothesis that TREM-1 affects monocytes extravasation and accumulation processes leading to atherogenesis and atherosclerotic plaque progression, possibly through increased inflammation and subsequent higher expression of sL-selectin.

Inherited Variation in Cytokine, Acute Phase Response, and Calcium Metabolism Genes Affects Susceptibility to Infective Endocarditis

Infective endocarditis (IE) is a septic inflammation of the endocardium. Recognition of microbial patterns, cytokine and acute phase responses, hemostasis features, and alterations in plasma lipid and calcium profile all have been reported to affect pathogenesis and clinical course of IE. Having recruited 123 patients with IE and 300 age-, sex-, and ethnicity-matched healthy blood donors, we profiled their genomic DNA for 35 functionally significant polymorphisms within the 22 selected genes involved in the abovementioned pathways, with the further genetic association analysis. We found that the G/A genotype of the rs1143634 polymorphism within the IL1B gene, the G/T genotype of the rs3212227 polymorphism within the IL12B gene, the A/G genotype of the rs1130864 polymorphism within the CRP gene, and the G allele of the rs1801197 polymorphism within the CALCR gene were associated with a decreased risk of IE whereas the T/T genotype of the rs1205 polymorphism within the CRP gene was associated with a higher risk of IE. Furthermore, heterozygous genotypes of the rs1143634 and rs3212227 polymorphisms were associated with the higher plasma levels of IL-1β and IL-12, respectively. Our results indicate that inherited variation in the cytokine, acute phase response, and calcium metabolism pathways may be linked to IE.

Soluble triggering receptor expressed on myeloid cell-1 (sTREM-1): a potential biomarker for the diagnosis of infectious diseases

Sensitive and useful biomarkers for the diagnosis and prognosis of infectious diseases have been widely developed. An example of these biomarkers is triggering receptor expressed on myeloid cell-1 (TREM-1), which is a cell surface receptor expressed on monocytes/macrophages and neutrophils. TREM-1 amplifies inflammation by activating the TREM-1/DAP12 pathway. This pathway is triggered by the interaction of TREM-1 with ligands or stimulation by bacterial lipopolysaccharide. Consequently, pro-inflammatory cytokines and chemokines are secreted. Soluble TREM-1 (sTREM-1) is a special form of TREM-1 that can be directly tested in human body fluids and well-known biomarker for infectious diseases. sTREM-1 level can be potentially used for the early diagnosis and prognosis prediction of some infectious diseases, including infectious pleural effusion, lung infections, sepsis, bacterial meningitis, viral infections (e.g., Crimean Congo hemorrhagic fever and dengue fever), fungal infections (e.g., Aspergillus infection), and burn-related infections. sTREM-1 is a more sensitive and specific biomarker than traditional indices, such as C-reactive protein and procalcitonin levels, for these infectious diseases. Therefore, sTREM-1 is a feasible biomarker for the targeted therapy and rapid and early diagnosis of infectious diseases.

The Role of TLR2, TLR4, and TLR9 in the Pathogenesis of Atherosclerosis

Toll-like receptors (TLRs) are key players in the pathogenesis of inflammatory conditions including coronary arterial disease (CAD). They are expressed by a variety of immune cells where they recognize pathogen-associated molecular patterns (PAMPs). TLRs recruit adaptor molecules, including myeloid differentiation primary response protein (MYD88) and TIRF-related adaptor protein (TRAM), to mediate activation of MAPKs and NF-kappa B pathways. They are associated with the development of CAD through various mechanisms. TLR4 is expressed in lipid-rich and atherosclerotic plaques. In TLR2^−/− and TLR4^−/− mice, atherosclerosis-associated inflammation was diminished. Moreover, TLR2 and TLR4 may induce expression of Wnt5a in advanced staged atheromatous plaque leading to activation of the inflammatory processes. TLR9 is activated by CpG motifs in nucleic acids and have been implicated in macrophage activation and the uptake of oxLDL from the circulation. Furthermore, TLR9 also stimulates interferon-α (INF-α) secretion and increases cytotoxic activity of CD4⁺ T-cells towards coronary artery tunica media smooth muscle cells. This review outlines the pathophysiological role of TLR2, TLR4, and TLR9 in atherosclerosis, focusing on evidence from animal models of the disease.

Genetic association of Toll-like receptor 4 gene and coronary artery disease in a Chinese Han population

PURPOSE

Toll-like receptor 4 (TLR4) is known to be involved in innate immunity and inflammatory responses that play important roles in the pathogenesis of coronary artery disease (CAD). But the relationship between TLR4 gene and CAD has yet to be investigated. The present study aimed to evaluate the association of TLR4 gene polymorphisms with CAD susceptibility in a Chinese Han population.

METHODS

A total of 1094 subjects (577 unrelated patients with CAD and 517 controls) were recruited between 2008 and 2012. Three tag SNPs (rs1927907, rs1927911 and rs11536889) present in the TLR4 gene were genotyped using Sequenom Mass-ARRAY system.

RESULTS

The genotypic distributions of the three SNPs were not deviate from Hardy-Weinberg equilibrium. There was no significant difference in distributions of allelic frequencies of each SNPs between healthy controls and CAD patients (P > 0.05). Genotype frequencies of TLR4 gene did not show any statistically significant difference between the two groups in co-dominant, dominant or recessive genetic models (P > 0.05). The frequency of haplotypes in the case group was similar to that in the control group (P > 0.05).

CONCLUSION

TLR4 gene do not relate to genetic susceptibility of CAD in the Chinese Han population.

A Genomics-Based Model for Prediction of Severe Bioprosthetic Mitral Valve Calcification

Severe bioprosthetic mitral valve calcification is a significant problem in cardiovascular surgery. Unfortunately, clinical markers did not demonstrate efficacy in prediction of severe bioprosthetic mitral valve calcification. Here, we examined whether a genomics-based approach is efficient in predicting the risk of severe bioprosthetic mitral valve calcification. A total of 124 consecutive Russian patients who underwent mitral valve replacement surgery were recruited. We investigated the associations of the inherited variation in innate immunity, lipid metabolism and calcium metabolism genes with severe bioprosthetic mitral valve calcification. Genotyping was conducted utilizing the TaqMan assay. Eight gene polymorphisms were significantly associated with severe bioprosthetic mitral valve calcification and were therefore included into stepwise logistic regression which identified male gender, the T/T genotype of the rs3775073 polymorphism within the TLR6 gene, the C/T genotype of the rs2229238 polymorphism within the IL6R gene, and the A/A genotype of the rs10455872 polymorphism within the LPA gene as independent predictors of severe bioprosthetic mitral valve calcification. The developed genomics-based model had fair predictive value with area under the receiver operating characteristic (ROC) curve of 0.73. In conclusion, our genomics-based approach is efficient for the prediction of severe bioprosthetic mitral valve calcification.