A preliminary study of the relationship between promoter methylation of the ABCG1, GALNT2 and HMGCR genes and coronary heart disease.

To investigate the association of ABCG1, GALNT2 and HMGCR genes promoter DNA methylation with coronary heart disease (CHD) and explore the interaction between their methylation status and the CHD patients' clinical characteristics in Han Chinese population.Methylation-specific polymerase chain reaction (MSP) technology was used to examine the role of the aberrant gene promoter methylation in CHD in Han Chinese population. A total of 85 CHD patients and 54 participants without CHD confirmed by angiography were recruited. 82.8% of the participants with ABCG1 gene promoter hypermethylation have CHD, while only 17.4% of the participants without hypermethylation have it. The average age of the participants with GALNT2 gene promoter hypermethylation is 62.10 ± 8.21, while that of the participants without hypermethylation is 57.28 ± 9.87; in the former group, 75.4% of the participants have CHD, compared to only 50% in the latter group. As for the HMGCR gene, the average age of the participants with promoter hypermethylation is 63.24 ± 8.10 and that of the participants without hypermethylation is 57.79 ± 9.55; its promoter hypermethylation is likely to be related to smoking. Our results indicated a significant statistical association of promoter methylation of the ABCG1 gene with increased risk of CHD (OR = 19.966; 95% CI, 7.319-54.468; P*<0.001; P*: adjusted for age, gender, smoking, lipid level, hypertension, and diabetes). Similar results were obtained for that of the GALNT2 gene (OR = 2.978; 95% CI, 1.335-6.646; P* = 0.008), but not of HMGCR gene (OR = 1.388; 95% CI, 0.572-3.371; P*  = 0.469).The present work provides evidence to support the association of promoter DNA methylation status with the risk profile of CHD. Our data indicates that promoter DNA hypermethylation of the ABCG1 and GALNT2 genes, but not the HMGCR gene, is associated with an increased risk of CHD. CHD, smoking and aging are likely to be the important factors influencing DNA hypermethylation

Positive Association between GCKR rs780093 Polymorphism and Coronary Heart Disease in the Aged Han Chinese

Objective. Previous studies have confirmed that GCKR rs780093 polymorphism is associated with triglyceride (TG), a known risk factor of coronary heart disease (CHD). The goal of our study is to explore the association of GCKR rs780093 polymorphism with CHD in Han Chinese population. Methods and Results. A total of 568 CHD cases and 494 non-CHD controls were enrolled in the current case-control study. Genotyping was done using melting temperature shift (Tm-shift) approach. Our results also showed that GCKR rs780093 polymorphism was significantly associated with TG level (P=0.0016). Although there was no significant association between cases and controls (P>0.05), a breakdown analysis by age yielded a significant association of GCKR rs780093 polymorphism with CHD in individuals aged 65 and older (genotype: χ2=6.86; df = 2; P=0.03; allele: χ2=4.11; df = 1; P=0.04). Conclusion. Our findings confirmed the contribution of GCKR rs780093 polymorphism to TG metabolism and demonstrated GCKR rs780093 as a risk factor of CHD in individuals aged 65 and older

Meta-Analyses of <i>KIF6</i> Trp719Arg in Coronary Heart Disease and Statin Therapeutic Effect

Aims: The goal of our study is to assess the contribution of KIF6 Trp719Arg to both the risk of CHD and the efficacy of statin therapy in CHD patients.Methods and Results: Meta-analysis of 8 prospective studies among 77,400 Caucasians provides evidence that 719Arg increases the risk of CHD (PP = 0.642, OR = 1.02, 95% CI = 0.95–1.08). This suggests that the contribution of Trp719Arg to CHD varies in different ethnic groups. Additional meta-analysis also shows that statin therapy only benefit the vascular patients carry 719Arg allele (PP = 0.04, χ2 = 4.228, df = 1, odd ratio (OR) = 1.979, 95% confidence interval (CI) = 1.023–3.828). Similar trends are observed for post hoc analysis between female CHD cases and female healthy controls (dominant model: P = 0.04, χ2 = 4.231, df = 1, OR = 2.015, 95% CI = 1.024–3.964). Non-genetic CHD risk factors are not controlled in these analyses.Conclusions: Our meta-analysis demonstrates the role of Trp719Arg of KIF6 gene in the risk of CHD in Caucasians. The meta-analysis also suggests the role of this variant in statin therapeutic response in vascular diseases. Our case-control study suggests that Trp719Arg of KIF6 gene is associated with CHD in female Han Chinese through a post hoc analysis.</p

Pharmacologic Approach to Defective Protein Trafficking in the E637K-hERG Mutant with PD-118057 and Thapsigargin

<div><p>Background</p><p>Treatment of LQT2 is inadequate. Many drugs which can pharmacologically rescue defective protein trafficking in LQT2 also result in potent blockade of HERG current, negating their therapeutic benefit. It is reported that PD-118057 and thapsigargin can rescue LQT2 without hERG channel blockade, but the precise mechanism of action is unknown. Furthermore, the effect of PD-118057 and thapsigargin on the dominant negative E637K-hERG mutant has not been previously investigated.</p><p>Objective</p><p>In this study, we investigated: (a) the effect of PD-118057 and thapsigargin on the current amplitudes of WT-hERG and WT/E637K-hERG channels; (b) the effect of PD-118057 and thapsigargin on the biophysical properties of WT-hERG and WT/E637K-hERG channels; (c) whether drug treatment can rescue channel processing and trafficking defects of the WT/E637K-hERG mutant.</p><p>Methods</p><p>The whole-cell Patch-clamp technique was used to assess the effect of PD-118057 and thapsigargin on the electrophysiological characteristics of the rapidly activating delayed rectifier K⁺ current (I_kr) of the hERG protein channel. Western blot was done to investigate pharmacological rescue on hERG protein channel function.</p><p>Results</p><p>In our study, PD-118057 was shown to significantly enhance both the maximum current amplitude and tail current amplitude, but did not alter the gating and kinetic properties of the WT-hERG channel, with the exception of accelerating steady-state inactivation. Additionally, thapsigargin shows a similar result as PD-118057 for the WT-hERG channel, but with the exception of attenuating steady-state inactivation. However, for the WT/E637K-hERG channel, PD-118057 had no effect on either the current or on the gating and kinetic properties. Furthermore, thapsigargin treatment did not alter the current or the gating and kinetic properties of the WT/E637K-hERG channel, with the exception of opening at more positive voltages.</p><p>Conclusion</p><p>Our findings illustrate that neither PD-118057 nor thapsigargin play a role in correcting the dominant-negative effect of the E637K-hERG mutant.</p></div

Methylation percent of the <i>ABCG1</i>, <i>GALNT2</i> and <i>HMGCR</i> genes promoter in the CHD cases and Non-CHD controls according to subgroup analysis by total samples and gender.

<p>Methylation percent of the <i>ABCG1</i>, <i>GALNT2</i> and <i>HMGCR</i> genes promoter in the CHD cases and Non-CHD controls according to subgroup analysis by total samples and gender.</p

Characteristics of all subjects according to subgroup analysis by CHD status and gender.

<p>Values are given as mean±s.e.; NA: denotes not applicable.</p><p>CHD: coronary heart disease; TC: total cholesterol; HDL: high density lipoprotein; LDL: low density lipoprotein; ALT: alanine aminotransferase; AST: aspartate aminotransferase.</p

Association of DNA hypermethylationed <i>ABCG1</i>, <i>GALNT2</i> and <i>HMGCR</i> genes with clinic characteristics.

<p>M: methylationed; U: unmethylationed; <i>P</i>-value*: adjusted for age, gender, smoking (smoker vs never smoker), lipid level, history of hypertension, and history of diabetes by Cox regression. <i>P</i><0.05 is considered statistically significant.</p

Typical methylation analysis result of the <i>ABCG1</i>, <i>GALNT2</i> and <i>HMGCR</i> genes promoter regions of by MSP.

<p>MW: molecular weight DNA marker (100-bp DNA ladder). 1–6 were CHD patients, 7–12 were Non-CHD controls; M for methylated specific primers; U for the unmethylated specific primers; PCR product indicated the presence of methylated or unmethylated promoter of <i>ABCG1</i>, <i>GALNT2</i> and <i>HMGCR</i> for primer M or primer U.</p

Primers for MSP of the <i>ABCG1</i>, <i>GALNT2</i> and <i>HMGCR</i> genes.

<p>MSP: methylation-specific polymerase chain reaction; M: methylation-specific primers; U: unmethylation-specific primers.</p

Methylation status of the <i>ABCG1</i>, <i>GALNT2</i> and <i>HMGCR</i> genes promoter in the CHD cases and Non-CHD controls according to subgroup analysis by total samples and gender.

<p>OR: odds ratio; CI: confidence interval; <i>P</i>-value: probability from the Pearson Chi-Square exact test comparing the methylation status for CHD.</p><p>Cases and Non-CHD controls; <i>P</i>-value*: adjusted for age, gender, smoking (smoker vs never smoker), lipid level, history of hypertension, and history of diabetes by Cox regression. <i>P</i><0.05 is considered statistically significant.</p