Association of the genetic markers for myocardial infarction with sudden cardiac death

Cardiac human bitter taste receptors contain naturally occurring variants that alter function

Bitter taste receptors (T2R) are a subfamily of G protein-coupled receptors that enable humans to detect aversive and toxic substances. The ability to discern bitter compounds varies between individuals and is attributed mainly to naturally occurring T2R polymorphisms. T2Rs are also expressed in numerous non-gustatory tissues, including the heart, indicating potential contributions to cardiovascular physiology. In this study. T2Rs that have previously been identified in human cardiac tissues (T2Rs - 10, 14, 30, 31, 46 and 50) and their naturally occurring polymorphisms were functionally characterised. The ligand-dependent signaling responses of some T2R variants were completely abolished (T2R30 Leu252 and T2R46 Met228), whereas other receptor variants had moderate changes in their maximal response, but not potency, relative to wild type. Using a cAMP fluorescent biosensor, we reveal the productive coupling of T2R14, but not the T2R14 Phe201 variant, to endogenous Gαi. Modeling revealed that these variants resulted in altered interactions that generally affected ligand binding (T2R30 Leu252) or Gα protein interactions (T2R46 Met228 and T2R14 Phe201), rather than receptor structural stability. Interestingly, this study is the first to show a difference in signaling for T2R50 Tyr203 (rs1376251) which has been associated with cardiovascular disease. The observation of naturally occurring functional variation in the T2Rs with the greatest expression in the heart is important, as their discovery should prove useful in deciphering the role of T2Rs within the cardiovascular system.

Genome-Wide Variants Associated With Longitudinal Survival Outcomes Among Individuals With Coronary Artery Disease

Objective

Coronary artery disease (CAD) is an age-associated condition that greatly increases the risk of mortality. The purpose of this study was to identify gene variants associated with all-cause mortality among individuals with clinically phenotyped CAD using a genome-wide screening approach.

Approach and Results

We performed discovery (n = 684), replication (n = 1,088), and meta-analyses (N = 1,503) for association of genomic variants with survival outcome using secondary data from White participants with CAD from two GWAS sub-studies of the Duke Catheterization Genetics Biorepository. We modeled time from catheterization to death or last follow-up (median 7.1 years, max 12 years) using Cox multivariable regression analysis. Target statistical screening thresholds were p × 10^–8 for the discovery phase and Bonferroni-calculated p-values for the replication (p < 5.3 × 10^–4) and meta-analysis (p < 1.6 × 10^–3) phases. Genome-wide analysis of 785,945 autosomal SNPs revealed two SNPs (rs13007553 and rs587936) that had the same direction of effect across all three phases of the analysis, with suggestive p-value association in discovery and replication and significant meta-analysis association in models adjusted for clinical covariates. The rs13007553 SNP variant, LINC01250, which resides between MYTIL and EIPR1, conferred increased risk for all-cause mortality even after controlling for clinical covariates [HR 1.47, 95% CI 1.17–1.86, p(adj) = 1.07 × 10^–3 (discovery), p(adj) = 0.03 (replication), p(adj) = 9.53 × 10^–5 (meta-analysis)]. MYT1L is involved in neuronal differentiation. TSSC1 is involved in endosomal recycling and is implicated in breast cancer. The rs587936 variant annotated to DAB2IP was associated with increased survival time [HR 0.65, 95% CI 0.51–0.83, p(adj) = 4.79 × 10^–4 (discovery), p(adj) = 0.02 (replication), p(adj) = 2.25 × 10^–5 (meta-analysis)]. DAB2IP is a ras/GAP tumor suppressor gene which is highly expressed in vascular tissue. DAB2IP has multiple lines of evidence for protection against atherosclerosis.

Conclusion

Replicated findings identified two candidate genes for further study regarding association with survival in high-risk CAD patients: novel loci LINC01250 (rs13007553) and biologically relevant candidate DAB2IP (rs587936). These candidates did not overlap with validated longevity candidate genes. Future research could further define the role of common variants in survival outcomes for people with CAD and, ultimately, improve longitudinal outcomes for these patients.

Circular RNAs in Sudden Cardiac Death Related Diseases: Novel Biomarker for Clinical and Forensic Diagnosis

The prevention and diagnosis of sudden cardiac death (SCD) are among the most important keystones and challenges in clinical and forensic practice. However, the diagnostic value of the current biomarkers remains unresolved issues. Therefore, novel diagnostic biomarkers are urgently required to identify patients with early-stage cardiovascular diseases (CVD), and to assist in the postmortem diagnosis of SCD cases without typical cardiac damage. An increasing number of studies show that circular RNAs (circRNAs) have stable expressions in myocardial tissue, and their time- and tissue-specific expression levels might reflect the pathophysiological status of the heart, which makes them potential CVD biomarkers. In this article, we briefly introduced the biogenesis and functional characteristics of circRNAs. Moreover, we described the roles of circRNAs in multiple SCD-related diseases, including coronary artery disease (CAD), myocardial ischemia or infarction, arrhythmia, cardiomyopathy, and myocarditis, and discussed the application prospects and challenges of circRNAs as a novel biomarker in the clinical and forensic diagnosis of SCD.

Associations between PHACTR1 gene polymorphisms and pulse pressure in Chinese Han population

A genome-wide association study (GWAS) in Chinese twins was performed to explore associations between genes and pulse pressure (PP) in 2012, and detected a suggestive association in the phosphatase and actin regulator 1 (PHACTR1) gene on chromosome 6p24.1 (rs1223397, P=1.04e⁻⁰⁷). The purpose of the present study was to investigate associations of PHACTR1 gene polymorphisms with PP in a Chinese population. We recruited 347 subjects with PP ≥ 65 mmHg as cases and 359 subjects with 30 ≤ PP ≤ 45 mmHg as controls. Seven single nucleotide polymorphisms (SNPs) in the PHACTR1 gene were genotyped. Logistic regression was performed to explore associations between SNPs and PP in codominant, additive, dominant, recessive and overdominant models. The Pearson’s χ² test was applied to assess the relationships of haplotypes and PP. The A allele of rs9349379 had a positive effect on high PP. Multivariate logistic regression analysis showed that rs9349379 was significantly related to high PP in codominant [AA vs GG, 2.255 (1.132–4.492)], additive [GG vs GA vs AA, 1.368 (1.049–1.783)] and recessive [AA vs GA + GG, 2.062 (1.051–4.045)] models. The positive association between rs499818 and high PP was significant in codominant [AA vs GG, 3.483 (1.044–11.613)] and recessive [AA vs GG + GA, 3.716 (1.119–12.339)] models. No significant association of haplotypes with PP was detected. There was no significant interaction between six SNPs without strong linkage. In conclusion, the present study presents that rs9349379 and rs499818 in the PHACTR1 gene were significantly associated with PP in Chinese population. Future research should be conducted to confirm them.

A Bitter Taste in Your Heart

The human genome contains ∼29 bitter taste receptors (T2Rs), which are responsible for detecting thousands of bitter ligands, including toxic and aversive compounds. This sentinel function varies between individuals and is underpinned by naturally occurring T2R polymorphisms, which have also been associated with disease. Recent studies have reported the expression of T2Rs and their downstream signaling components within non-gustatory tissues, including the heart. Though the precise role of T2Rs in the heart remains unclear, evidence points toward a role in cardiac contractility and overall vascular tone. In this review, we summarize the extra-oral expression of T2Rs, focusing on evidence for expression in heart; we speculate on the range of potential ligands that may activate them; we define the possible signaling pathways they activate; and we argue that their discovery in heart predicts an, as yet, unappreciated cardiac physiology.

Case-Control Study on the Interaction Effects of rs10757278 Polymorphisms at 9p21 Locus and Traditional Risk Factors on Coronary Heart Disease in Xinjiang, China

OBJECTIVE

To study the interaction effects of rs10757278 polymorphisms at 9p21 locus and traditional risk factors on coronary heart disease (CHD) in Xinjiang, China.

METHODS

This case-control study consecutively enrolled 310 unrelated consecutive CHD patients aged 18-70 years old. All study participants were recruited between January and December 2017 from The Heart Center of The First Affiliated Hospital of Xinjiang Medical University. CHD patients were confirmed by coronary angiography (≥50% diameter stenosis in at least one of the major coronary arteries) according to the American Heart Association criteria for the confirmation of CHD. Healthy subjects were randomly selected from the occupational population, who received physical examination in our hospital and matched to cases on the basis of age (±3 years) and sex, those without medical history of cardiovascular diseases, and 536 subjects were selected as the control group after medical history inquiry, physical examination, cardiac ultrasound, electrocardiogram, and other blood biochemical examinations in the hospital. The occupational stress was evaluated by an effort-reward imbalance questionnaire. An epidemiological survey was conducted to collect clinical data. Chi-squared test, analysis of variance, and binary logistic regression analysis were adopted.

RESULTS

Both the case and the control groups showed significant difference in smoking, drinking, physical activity, hypertension, diabetes mellitus, family history of CHD, and body mass index (BMI) (all P < 0.05); prevalence of CHD was not related to occupational stress. There was no significant difference in occupational stress level between the 2 groups (P > 0.05); Differences in rs10757278 genotype between the case group and the control groups were statistically significant; binary logistic regression analysis was used to evaluate the risk factors of CHD. After adjustment for age and sex, significant increased risk effects for CHD were found to be associated with smoking [odds ratio (OR) = 2.311; 95% confidence interval (CI): 1.04-2.499; P < 0.001], physical exercise (OR = 1.365; 95% CI: 1.137-1.639; P < 0.001), hypertension (OR = 4.627; 95% CI: 2.165-10.764; P < 0.001), family history of CHD (OR = 4.103; 95% CI: 3.169-6.892; P < 0.001), BMI (OR = 2.484; 95% CI: 2.036-3.03; P < 0.001), and GG genotype at rs10757278 (OR = 1.978; 95% CI: 1.413-2.769; P < 0.001); We noted that a significant interaction association between GG genotype at rs10757278 and CHD differs across categories of smoking, hypertension, family history of CHD, and BMI.

CONCLUSION

GG genotype at rs10757278 may be a risk factor for CHD. And there are interaction effects between GG genotype of rs10757278 in region 9p21 gene and traditional risk factors.

Expression profiles and potential functions of long non-coding RNA in stable angina pectoris patients from Uyghur population of China

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nt that are involved in cardiovascular diseases (CVDs). To determine whether lncRNAs are involved in stable angina pectoris (SAP), we analysed the expression profile of lncRNAs and mRNAs on a genome-wide scale in SAP of Uyghur population. Five pairs of SAP patients and healthy controls were screened by an Agilent microarray (human lncRNA + mRNA Array V4.0). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the lncRNA expression levels in 50 SAP and 50 controls. Data analyses were performed using R and Bioconductor. A total of 1871 up- and 231 down-regulated lncRNAs were identified to be differentially expressed in the peripheral blood mononuclear cells (PBMCs). Microarray analysis results identified the lncRNAs NR_037652.1, ENST00000607654.1, ENST00000589524.1 and uc004bhb.3, which were confirmed by qRT-PCR. Among screened lncRNAs, the annotation result of their co-expressed mRNAs showed that the most significantly related pathways were the NF-κB signalling pathway, apoptosis and the p53 signalling pathway, while the main significantly related diseases were the cholesterol, calcium and coronary disease. Our study indicated that clusters of lncRNAs were significantly differentially expressed between SAP patients and matched controls. These lncRNAs may play a significant role in SAP development and could serve as biomarkers and potential targets for the future treatment of SAP.

Effects of CDKN2B-AS1 polymorphisms on the susceptibility to coronary heart disease

Background

Coronary heart disease (CHD) is one of the most severe cardiovascular diseases. Cyclin‐dependent kinase inhibitor 2B antisense RNA 1 (CDKN2B‐AS1) is a significant susceptibility locus for cardiovascular disease by regulating inflammation response and cell cycle. The aim of this study was to assess whether CDKN2B‐AS1 polymorphisms are associated with CHD risk in the Chinese Han population.

Methods

A total of 501 CHD patients and 496 healthy controls were recruited from Central South University Xiangya School of Medicine Affiliated Haikou Hospital, five CDKN2B‐AS1 polymorphisms (rs10115049, rs75227345, rs2383205, rs10738606, and rs1333049) were analyzed by the Agena MassARRAY platform. The association of CDKN2B‐AS1 polymorphisms and CHD risk was determined by odd ratios (OR) and 95% confidence intervals (CI) using logistic regression.

Results

CDKN2B‐AS1 rs10738606 was significantly associated with CHD under codominant (p = .03), dominant (p = .019), recessive (p = .010), additive (p = .003), and allele (p = .003) models. Gender‐based subgroup tests showed that four polymorphisms (rs75227345, rs2383205, rs10738606 and rs1333049) were associated with CHD in males (p < .05). And age‐based subgroup tests indicated that rs2383205 and rs10738606 were associated with CHD among individuals, respectively (p < .05). For CHD patients, rs1333049 decreased the risk of diabetes under heterozygote (p = .014) and dominant (p = .024) models.

Conclusions

In conclusion, CDKN2B‐AS1 polymorphisms were associated with CHD risk in the combined or subgroup tests, suggesting an important role of CDKN2B‐AS1 in CHD susceptibility.

Usefulness of Single Nucleotide Polymorphisms as Predictors of Sudden Cardiac Death

The pathophysiology of sudden cardiac death (SCD) remains incompletely understood. Genetic mutations can create a favorable substrate for SCD. Our aim is to evaluate the evidence of single nucleotide polymorphisms (SNPs) as predictors of SCD. We searched the Medline database (2000 to 2017) and selected all case-control or cohort studies that reported associations between SNPs and SCD. Our search terms included "polymorphisms" and "sudden death." We collected the study design, population ethnic background, gene testing strategy, the association between the SNP and SCD, and the cardiovascular comorbidities of the population. Our search yielded 723 studies, of which we included 24 based upon our inclusion criteria. The studies had a total population of 78,165 participants, with a median age of 62.5 years (IQR 56 to 66) and 35% (IQR 13 to 32) were female. Almost all studies were conducted in white patients of European descent and the most commonly used genetic strategy was candidate gene panels. Fifteen of the studies had a case-control design that included SCD patients without known heart disease as the comparison group and the other 9 studies included patients with heart failure and coronary artery disease. The studies evaluated 53 SNPs and the most common genetic loci were SCN5A, RyR2, CASQ2, NOSA1P, and AGTR. SNPs with the 3 strongest statistically significant ORs >1 were: rs6684209 of CASQ2 (odds ratio [OR] 19), rs3814843 of CALM1 (OR 5.5), and rs35594137 of GJA5 (OR 3.6). In Conclusion, many SNPs are associated with SCD, with the strongest associations seen in SNPs of genes related to intracellular calcium handling. These findings were generated primarily using a candidate gene strategy in white patients with European descent.