Probing the epigenetic signatures in subjects with coronary artery disease.

Depletion of S-adenosyl methionine and 5-methyltetrahydrofolate; and elevation of total plasma homocysteine were documented in CAD patients, which might modulate the gene-specific methylation status and alter their expression. In this study, we have aimed to delineate CAD-specific epigenetic signatures by investigating the methylation and expression of 11 candidate genes i.e. ABCG1, LIPC, PLTP, IL-6, TNF-α, CDKN2A, CDKN2B, F2RL3, FGF2, P66 and TGFBR3. The methylation-specific PCR and qRT-PCR were used to assess the methylation status and the expression of candidate genes, respectively. CAD patients showed the upregulation of IL-6, TNF-α, CDKN2A, CDKN2B, F2RL3, FGF2, P66, and TGFBR3. Hypomethylation of CDKN2A loci was shown to increase risk for CAD by 1.79-folds (95% CI 1.22-2.63). Classification and regression tree (CART) model of gene expression showed increased risk for CAD with F2RL3 > 3.4-fold, while demonstrating risk reduction with F2RL3 < 3.4-fold and IL-6 < 7.7-folds. This CAD prediction model showed the excellent sensitivity (0.98, 95% CI 0.88-1.00), specificity (0.91, 95% CI 0.86-0.92), positive predictive value (0.82, 95% CI 0.75-0.84), and negative predictive value (0.99, 95% CI 0.94-1.00) with an overall accuracy of 92.8% (95% CI 87.0-94.1%). Folate and B12 deficiencies were observed in CAD cases, which were shown to contribute to hypomethylation and upregulation of the prime candidate genes i.e. CDKN2A and F2RL3. Early onset diabetes was associated with IL-6 and TNF-α hypomethylation and upregulation of CDKN2A. The expression of F2RL3 and IL-6 (or) hypomethylation status at CDKN2A locus are potential biomarkers in CAD risk prediction. Early epigenetic imprints of CAD were observed in early onset diabetes. Folate and B12 deficiencies are the contributing factors to these changes in CAD-specific epigenetic signatures.

The Mediterranean diet reduces the genetic risk of chromosome 9p21 for myocardial infarction in an Asian population community cohort.

The interaction of genetic susceptibility and dietary habits in cardiovascular disease (CVD) remains undetermined. The purpose of this study was to investigate whether a Mediterranean dietary style modified the genetic risk of developing CVD in a Chinese cohort. A total of 2098 subjects with dietary information from a Chinese community cohort (CVDFACTS) were enrolled. Candidate genes, including SNP markers rs1333049 (CDKN2B, 9p21.3), rs17465637 (MIA3, 1q41) and rs501120 (CXCL12, 10q11.21), were genotyped to analyze the association with future CVD. The impact of dietary pattern was also analyzed according to adherence to the diet using the Mediterranean Diet Score (MDS). After an average follow-up of 7.8 years, only the C risk allele of rs1333049 at chromosome 9p21.3 was associated with a higher risk of MI with either an additive [HR = 1.78, 95% CI:1.23-2.5] or a recessive model [HR = 2.40, 95% CI: 1.42-4.04], and the CC genotype had a higher risk of developing MI (p = 0.009, log-rank test). There was no significant difference in the association of the lipid profile with future CV outcomes among the MDS tertiles. However, the high MI risk of the CC genotype in individuals consuming a less healthy diet (MDS1) (HR: 6.39, 95% CI: 1.74-23.43) significantly decreased to 2.38 (95% CI: 0.57-10.04) in individuals consuming a healthier diet (MDS3), indicating that a healthier dietary pattern (higher MDS) modified the risk of developing MI in carriers of variants in CDKN2B. In conclusion, genetic variants of CDKN2B at 9p21 were significantly associated with future MI risk in a Chinese cohort, and the genetic risk of MI could be modified by a healthier diet.

Relationship Between P15 Gene Mutation and Formation and Metastasis of Malignant Osteosarcoma.

BACKGROUND As a type of primary malignant bone tumor, osteosarcoma has high incidence and poor prognosis, and is predisposed for pulmonary metastasis. The abnormal expression of P15 gene directly participates in the invasion of various cancers. Therefore, this study investigated the gene mutation of P15 in both primary lesion and pulmonary metastasis lesion of osteosarcoma in a rat model, in an attempt to elucidate the value of P15 gene as a biological marker. MATERIAL AND METHODS A total of 60 SD rats were randomly divided into 2 groups. Model rats had injection of osteosarcoma UMR-106 cells (5×106) inoculated underneath the right forelimb skin, while control rats received saline injection instead. Six rats were sacrificed after 0, 1, 2, 4, and 6 weeks of the inoculation. Tissue samples from inoculation sites and lungs were extracted for measuring the tumor size. SP immunohistochemical (IHC) staining was used to detect the positive expression rate, while P15 gene mutation was detected by PCR method. RESULTS With the elongation of inoculation time, tumor size was significantly increased (p<0.05). The positive expression rates in both primary and pulmonary metastasis lesions were also significantly elevated (p<0.05). The occurrence rate of P15 gene mutation in model rats was significantly elevated and showed a correlation with the tumor formation (r=0.998, p<0.05). CONCLUSIONS The P15 gene mutation was significantly correlated with osteosarcoma formation and metastasis towards the pulmonary tissue, suggesting its potency as a novel biological marker for early diagnosis of osteosarcoma.

Increased mitochondrial DNA copy number in occupations associated with low-dose benzene exposure.

BACKGROUND: Benzene is an established leukemogen at high exposure levels. Although low-level benzene exposure is widespread and may induce oxidative damage, no mechanistic biomarkers are available to detect biological dysfunction at low doses. OBJECTIVES: Our goals were to determine in a large multicenter cross-sectional study whether low-level benzene is associated with increased blood mitochondrial DNA copy number (mtDNAcn, a biological oxidative response to mitochondrial DNA damage and dysfunction) and to explore potential links between mtDNAcn and leukemia-related epigenetic markers. METHODS: We measured blood relative mtDNAcn by real-time polymerase chain reaction in 341 individuals selected from various occupational groups with low-level benzene exposures (> 100 times lower than the Occupational Safety and Health Administration/European Union standards) and 178 referents from three Italian cities (Genoa, Milan, Cagliari). RESULTS: In each city, benzene-exposed participants showed higher mtDNAcn than referents: mtDNAcn was 0.90 relative units in Genoa bus drivers and 0.75 in referents (p = 0.019); 0.90 in Milan gas station attendants, 1.10 in police officers, and 0.75 in referents (p-trend = 0.008); 1.63 in Cagliari petrochemical plant workers, 1.25 in referents close to the plant, and 0.90 in referents farther from the plant (p-trend = 0.046). Using covariate-adjusted regression models, we estimated that an interquartile range increase in personal airborne benzene was associated with percent increases in mtDNAcn equal to 10.5% in Genoa (p = 0.014), 8.2% (p = 0.008) in Milan, 7.5% in Cagliari (p = 0.22), and 10.3% in all cities combined (p < 0.001). Using methylation data available for the Milan participants, we found that mtDNAcn was associated with LINE-1 hypomethylation (-2.41%; p = 0.007) and p15 hypermethylation (+15.95%, p = 0.008). CONCLUSIONS: Blood MtDNAcn was increased in persons exposed to low benzene levels, potentially reflecting mitochondrial DNA damage and dysfunction.

Polymorphisms in promoter sequences of the p15 ( INK4B ) and PTEN genes of normal Japanese individuals.

Gene promoter regions of p15(INK4B), a cyclin-dependent kinase inhibitor, and phosphatase and tensin homolog (PTEN), a dual-function protein and lipid phosphatase, interact with regulatory factors for gene transcription and methylation. Normal individuals exhibit sequence polymorphisms in these regulatory genes. We isolated genomic DNA from whole blood of healthy Japanese individuals and sequenced promoter regions of the p15 ( INK4B ) and PTEN genes. We also examined the influence of polymorphisms on promoter activity in several cell lines. We identified polymorphisms at positions -699, -394, and -242 and an insertion at position -320 in the p15 ( INK4B ) gene and a polymorphism at position -1142 in the PTEN gene. Reporter gene analysis revealed that these polymorphisms influenced transcriptional regulation in their cell lines. Our results indicate for the first time that promoter sequences of the p15 ( INK4B ) and PTEN genes differ among normal Japanese individuals and that promoter polymorphisms can influence gene transcription.