Correlations between gene expression highlight a different activation of ACE/TLR4/PTGS2 signaling in symptomatic and asymptomatic plaques in atherosclerotic patients.

Inflammation has a key role and translates the effects of many known risk factors for the disease in atherosclerotic vulnerable plaques. Aiming to look into the elements that induce the development of either a vulnerable or stable atherosclerotic plaque, and considering that inflammation has a central role in the progression of lesions, we analyzed the expression of genes involved in the ACE/TLR4/PTGS2 signaling in carotid plaques of symptomatic and asymptomatic patients. Patients with internal carotid artery stenosis undergoing carotid endarterectomy at Verona University Hospital were included in this study. A total of 71 patients was considered for gene expression analysis (29 atherothrombotic stroke patients and 42 asymptomatic patients). Total RNA was extracted from the excised plaques and expression of PTGS2, ACE, TLR4, PTGER4, PTGER3, EPRAP and ACSL4 genes was analyzed by real-time PCR. The correlation between the pair of genes was studied by Spearman coefficient. From the analyzed genes, we did not observe any individual difference in gene expression but the network of co-expressed genes suggests a different activation of pathways in the two groups of plaques.

HDAC9, TWIST1 and FERD3L gene expression in asymptomatic stable and unstable carotid plaques.

BACKGROUND AND OBJECTIVES: A variant located at the end of HDAC9 gene within clusters of DNAse I sensitivity zones and histone modification hotspots has been associated with large vessel stroke and could be linked to plaque instability. The aim of the study is to define if an altered expression of HDAC9, TWIST1 and FERD3L genes could be involved in plaque vulnerability. METHODS: Histological classification and gene expression analysis were performed in 6 stable and 16 unstable plaques obtained from asymptomatic patients undergoing endarterectomy. Gene expression was analysed by real-time PCR. RESULTS AND CONCLUSIONS: TWIST1 gene expression resulted higher in stable plaques (P < 0.02). HDAC9 gene expression followed a similar trend (P = 0.11). These results highlighting the significant correlation between TWIST and HDAC9 gene expression suggest that both genes may contribute to plaque stability in a coordinated way.

Association of promoter polymorphism -765G>C in the PTGS2 gene with malignant melanoma in Italian patients and its correlation to gene expression in dermal fibroblasts.

Prostaglandins, especially prostaglandin E synthetase (PGE2), influence carcinogenesis by promoting cell proliferation, inhibiting apoptosis, stimulating angiogenesis and mediating immune suppression. Cyclooxygenase-2, coded by the PTGS2 gene, is the key enzyme in the production of prostaglandins. In melanoma, Cox-2 is over expressed in primary malignant melanoma (MM) and in their corresponding metastases. Polymorphisms in the promoter region of PTGS2 gene can modulate gene expression and could modify individual susceptibility to MM. Two hundred and forty melanoma patients and 342 controls were genotyped for polymorphisms -765G>C (rs20417) and -1195A>G (rs689466). Allele -765C frequency was significantly higher in melanoma patients. No allele frequency differences for -1195A>G polymorphism were observed. Haplotype analysis revealed that the haplotypes carrying the minor alleles were associated to a higher risk of melanoma (P = 0.02). Expression analysis showed that allele -765C is associated to a higher gene expression and could represent a risk allele by affecting the functionality of the promoter.

Cyclooxygenase 2, toll-like receptor 4 and interleukin 1ß mRNA expression in atherosclerotic plaques of type 2 diabetic patients.

OBJECTIVES AND DESIGN: Inflammation has a prominent role in the development of atherosclerosis. Type 2 diabetes could contribute to atherosclerosis development by promoting inflammation. This status might accelerate changes in intrinsic vascular wall cells and favor plaque formation. Cyclooxygenase 2 (COX-2) is highly expressed in atherosclerotic plaques. COX-2 gene expression is promoted through activation of toll-like receptor 4 (TLR4) and pro-inflammatory cytokine interleukin 1ß (IL1-ß). Aim of this study is to investigate whether expression profiles of pro-inflammatory genes such as COX-2, TLR4 and IL1-ß in atherosclerotic plaques are altered in type 2 diabetes (T2D). METHODS: Total RNA was isolated from plaques of atherosclerotic patients and expression of COX-2, TLR4, IL1-ß analyzed using real-time PCR. Histological analysis was performed on sections of the plaque to establish the degree of instability. RESULTS: Statistically significant differences in mRNA expression of COX-2 and IL1-ß were found in plaques of T2D compared with non-T2D patients. A multi-variable linear regression model suggests that COX-2 mRNA expression is affected by T2D pathology and IL1-ß mRNA expression in atherosclerotic plaques. CONCLUSIONS: Our results support the hypothesis that T2D pathology contributes in vivo to increase the inflammatory process associated with the atherosclerotic plaque formation, as shown by an increment of COX-2 and IL1-ß mRNA expression.

Polymorphism -2604G>A variants in TLR4 promoter are associated with different gene expression level in peripheral blood of atherosclerotic patients.

Toll-like receptor-4 (TLR4) is a primary receptor of the innate immune reaction and compelling evidence demonstrates its involvement in the pathogenesis of atherosclerosis and stroke. TLR4 is constitutively expressed on monocytes and endothelial cells; it is highly expressed in atherosclerotic plaques and in peripheral blood of patients after ischemic stroke. Polymorphisms in the promoter region that alter the transcriptional regulation of this gene may represent genetic risk factors involved in the predisposition to atherosclerotic disease. In this study we investigated the effect on TLR4 gene expression of three polymorphisms in the upstream regulatory region at positions -1607T>C/rs10759932, -2026A>G/rs1927914 and -2604G>A/rs10759931 in peripheral blood of atherosclerotic patients. RNA from individuals homozygous for the -2604A allele showed a lower expression of the gene when compared to patients carrying the counterparts GG+GA. Electrophoretic mobility shift assays showed differences in the electrophoretic mobility of the DNA-nuclear protein complexes formed by the G>A variants, suggesting that the two alleles differ in their binding affinity to transcriptional factors.

Expression of Circulating miR-17-92 Cluster and HDAC9 Gene in Atherosclerotic Patients with Unstable and Stable Carotid Plaques.

AIMS: The miR-17-92 cluster and the HDAC9 gene are involved in inflammatory, apoptotic, and angiogenic processes that are activated in the vulnerable carotid plaque. The aim of this research was to determine whether expression of one or more of the miRs of the miR-17-92 cluster and/or HDAC9 expression could represent biomarkers for patients with unstable atherosclerotic carotid plaques. MATERIALS AND METHODS: Plasma levels of miRs and HDAC9 expression in peripheral blood were analyzed by real-time PCR in patients with histologically classified stable or unstable plaques. RESULTS: No differences were observed between the two groups. DISCUSSION AND CONCLUSIONS: Levels of the miR-17-92 cluster in plasma and HDAC9 gene expression in peripheral blood cannot be considered appropriate biomarkers to identify patients with unstable plaques at risk of rupture.

Sex-specific effect of RNASEL rs486907 and miR-146a rs2910164 polymorphisms' interaction as a susceptibility factor for melanoma skin cancer.

The genetics of melanoma is complex and, in addition to environmental influences, numerous genes are involved or contribute toward melanoma predisposition. In this study, we evaluated the possible interaction between miR-146a and one of its putative targets ribonuclease L (RNASEL) in the risk of sporadic melanoma. Polymorphisms rs2910164 in miR-146a and rs486907 in the RNASEL gene have both independently been associated with the risk of different cancers, and an interaction between them has been observed in nonmelanoma skin cancer. Polymorphisms rs2910164 G/C and rs486907 A/G were genotyped by restriction fragment length polymorphism analysis in 304 sporadic melanoma patients and 314 control individuals. Genotype distribution between cases and controls for each of the two polymorphisms was compared using Fisher's exact test. Epistasis between the two polymorphisms was tested by a logistic regression model. In the present study, we observed a sex-specific effect of the miR-146a rs2910164 C allele restricted to individuals carrying the RNASEL rs486907 A allele as well. Men carrying this allelic combination have the highest risk of melanoma, whereas it seems to have no effect or even an opposite relationship to melanoma risk in the female population. The results reported in the present study suggest a sex-specific interaction between miR-146a and RNASEL genes in melanoma skin cancer susceptibility, and could account for possible discordant results in association studies when stratification according to sex is not performed.