Gene-smoking interactions in multiple Rho-GTPase pathway genes in an early-onset coronary artery disease cohort

miR-3646 promotes vascular inflammation and augments vascular smooth muscle cell proliferation and migration in progression of coronary artery disease by directly targeting RHOH

Coronary artery disease (CAD) is one of the leading causes of mortality and morbidity worldwide and the number of individuals at CAD risk is increasing. To better manage cardiovascular disease, improved tools for risk prediction including the identification of novel accurate biomarkers are needed. MicroRNAs (miRNAs) are small non-coding RNAs that modulate the expression of protein-coding genes at the post-transcription level and their dysregulated expression has been implicated in various pathogenic processes including cardiovascular disease. Circulating miRNAs have been widely recommended as potential biomarkers for many diseases including coronary artery disease. In the present study, we found that miR-3646 was significantly upregulated in the serum samples of CAD patients and in the mice with acute myocardial infarction (AMI) compared with the healthy control group via using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Moreover, the serum levels of miR-3646 were significantly positively correlated with the expression of IL-6 both in CAD patient samples and AMI mice samples. In human THP-1 macrophages, transfection with miR-3646 mimic elevated the expression of IL-6 while silence of miR-3646 suppressed the IL-6 level. Further exploration of the downstream targets of miR-3646 identified that blocking RHOH expression also could upregulate IL-6 expression. In addition, our findings also showed that miR-3646 promoted vascular smooth muscle cell (VSMC) proliferation and migration by targeting RHOH. These results demonstrate that the miR-3646-RHOH axis may serve as a key regulator in the progression of CAD by modulating vascular inflammation and regulating the biologic behaviors of VSMCs.

Serum Uric Acid as an Independent Risk Factor for the Presence and Severity of Early-Onset Coronary Artery Disease: A Case-Control Study

Serum uric acid (UA) is the final product of purine metabolism in humans. The present study is aimed at identifying the potential association between serum UA and early-onset coronary artery disease (EOCAD). The study population consisted of 1093 EOCAD patients aged ≤50 years, and 1117 age- and sex-matched apparently healthy people served as controls. The concentrations of UA were measured by uricase method. The severity of CAD was evaluated by Gensini score. The mean serum level of UA was 5.843 ± 1.479 mg/dl in EOCAD patients and 5.433 ± 1.529 mg/dl in controls. Serum UA levels were significantly higher in the EOCAD group than those in the control group (P < 0.001) and was an independent risk factor for EOCAD (OR = 1.100, 95% CI: 1.022–1.185). The early-onset myocardial infarction patients with 3-vessel disease had higher serum UA levels than those with 1- or 2-vessel disease. The serum UA levels of EOCAD patients with acute coronary syndrome were significantly higher than those with chronic coronary artery disease. EOCAD patients with hyperuricemia had higher Gensini scores than those without hyperuricemia. In addition, the serum UA levels were affected by drinking (P < 0.01) and were positively correlated with serum creatinine (r = 0.323) and weight (r = 0.327). Our results show that serum UA was an independent risk factor for EOCAD. The serum UA levels were associated with the presence and severity of EOCAD and suggested that UA may be involved in the progression of EOCAD.

A Schizophrenia-Linked KALRN Coding Variant Alters Neuron Morphology, Protein Function, and Transcript Stability

BACKGROUND

Large-scale genetic studies have revealed that rare sequence variants, including single nucleotide variants (SNVs), in glutamatergic synaptic genes are enriched in schizophrenia patients. However, the majority are too rare to show any association with disease and have not been examined functionally. One such SNV, KALRN-P2255T, displays a penetrance that greatly exceeds that of previously identified schizophrenia-associated SNVs. Therefore, we sought to characterize its effects on the function of kalirin (Kal)-9, a dual Ras-related C3 botulinum toxin substrate 1 and Ras homologue gene family, member A (RhoA) guanine nucleotide exchange factor, upregulated in human schizophrenia brain tissue.

METHODS

Kal9 was overexpressed in primary rat cortical neurons or human embryonic kidney 293 (HEK293) cells. The effects of the P2255T variant on dendritic branching, dendritic spine morphology, protein and messenger RNA stability, and catalytic activity were examined.

RESULTS

Kal9-P2255T leads to diminished basal dendritic branching and dendritic spine size, compared with wild-type Kal9. The P2255T SNV directly affected Kal9 protein function, causing increased RhoA activation in HEK293 cells, but had no effect on Ras-related C3 botulinum toxin substrate 1 activation. Consistent with human postmortem findings, we found that Kal9-P2255T protein levels were higher than those of wild-type Kal9 in neurons. Increased messenger RNA stability was detected in HEK293 cells, indicating that this was the cause of the higher protein levels. When analyzed together, increased intrinsic RhoA guanine nucleotide exchange factor catalytic activity combined with increased messenger RNA expression led to net enhancement of RhoA activation, known to negatively impact neuronal morphology.

CONCLUSIONS

Taken together, our data reveal a novel mechanism for disease-associated SNVs and provide a platform for modeling morphological changes in mental disorders.

Genetic Variant of Kalirin Gene Is Associated with Ischemic Stroke in a Chinese Han Population

INTRODUCTION

Ischemic stroke is a complex disorder resulting from the interplay of genetic and environmental factors. Previous studies showed that kalirin gene variations were associated with cardiovascular disease. However, the association between this gene and ischemic stroke was unknown. We performed this study to confirm if kalirin gene variation was associated with ischemic stroke.

METHODS

We enrolled 385 ischemic stroke patients and 362 controls from China. Three SNPs of kalirin gene were genotyped by means of ligase detection reaction-PCR method. Data was processed with SPSS and SHEsis platform.

RESULTS

SNP rs7620580 (dominant model: OR = 1.590, p = 0.002 and adjusted OR = 1.662, p = 0.014; additive model: OR = 1.490, p = 0.002 and adjusted OR = 1.636, p = 0.005; recessive model: OR = 2.686, p = 0.039) and SNP rs1708303 (dominant model: OR = 1.523, p = 0.007 and adjusted OR = 1.604, p = 0.028; additive model: OR = 1.438, p = 0.01 and adjusted OR = 1.476, p = 0.039) were associated with ischemic stroke. The GG genotype and G allele of SNP rs7620580 were associated with a risk for ischemic stroke with an adjusted OR of 3.195 and an OR of 1.446, respectively. Haplotype analysis revealed that A-T-G,G-T-A, and A-T-A haplotypes were associated with ischemic stroke.

CONCLUSIONS

Our results provide evidence that kalirin gene variations were associated with ischemic stroke in the Chinese Han population.

Water-pipe smoke condensate increases the internalization of Mycobacterium Bovis of type II alveolar epithelial cells (A549)

BACKGROUND

Tuberculosis (TB) is a major global health problem, and there is an association between tobacco smoke and TB. Water pipe smoking has become an increasing problem not only in Middle Eastern countries but also globally because users consider it as safer than cigarettes. The presence of high levels of toxic substances in water-pipe smoke may be a predisposing factor that enhances the incidence of pulmonary disorders. For example, uncontrolled macropinocytosis in alveolar epithelial cells following exposure to water-pipe smoke may predispose subjects to pulmonary infection. Here, we studied the effects of water-pipe condense (WPC) on the internalization of Mycobacterium Bovis BCG by macropinocytosis in the alveolar epithelial cell line A549.

METHODS

A549 cells were exposed to WPC (4 mg/ml) for 24, 48, 72 and 96 h. Cell viability was studied using the methyl thiazolyldipenyl-tetrazolium bromide (MTT) reduction assay and proliferation by bromodeoxyUridine (BrdU) incorporation. Cells were exposed to FITC-Dextran (1 mg/ml) (as a control) and FITC-BCG (MOI = 10) for 20 min at 37 °C before cells were collected and the uptake of BCG-FITC determined by flow cytometry. Similar experiments were performed at 4 °C as a control. The Rho-associated protein kinase (ROCK) inhibitor Y-27632 (1 μM) was used to assess the mechanism by which WPC enhanced BCG uptake.

RESULTS

WPC (4 mg/ml) increased the uptake of BCG-FITC after 72 (1.3 ± 0.1 fold, p < 0.05) and 96 (1.4 ± 0.05 fold, p < 0.05) hours. No effect on BCG-FITC uptake was observed at 24 or 48 h. WPC also significantly increased the uptake of FITC-Dextran (2.9 ± 0.3 fold, p < 0.05) after 24 h. WPC significantly decreased cell viability after 24 (84 ± 2%, p < 0.05), 48 (78±, 3%, p < 0.05), 72 (64 ± 2%, p < 0.05) and 96 h (45 ± 2%, p < 0.05). Y-27632 completely attenuated the increased uptake of BCG by WPC. Cell proliferation showed a decreasing trend in a time-dependent manner with WPC exposure.

CONCLUSION

WPC exposure increased epithelial cell endocytosis activity and death as well as enhancing their capacity for macropinocytosis. Our in vitro data indicates possible harmful effects of WPC on the ability of lung epithelial cells to phagocytose mycobacterium.

Increased serum concentrations of asymmetric dimethylarginine (ADMA) in patients with early-onset coronary artery disease

BACKGROUND

Asymmetric dimethylarginine (ADMA) has been associated with an increased risk of cardiovascular disease. We investigated the role of serum ADMA concentrations in early-onset coronary artery disease (EOCAD).

METHODS

Candidates for coronary artery angiography (age<50y for men and <55y for women) who met the inclusion criteria were enrolled in this study. Serum concentrations of ADMA were determined using ELISA. Severity of coronary atherosclerosis was estimated by number of diseased vessels.

RESULTS

A total of 601 subjects (286 with EOCAD patients and 315 controls) were included in the study. ADMA concentrations were found to be significantly higher in the EOCAD group (0.480±0.110μmol/l) than in the control group (0.457±0.091, P=0.007). ADMA concentrations significantly increased with the number of diseased vessels (P<0.001). In addition, serum ADMA concentrations were affected by diabetes mellitus and smoking status, and were positively correlated with serum creatinine and body mass index (BMI).

CONCLUSIONS

Our results show that serum ADMA concentrations were associated with the presence and severity of EOCAD, suggesting that ADMA may be involved in the progression of EOCAD.

Association Between Paraoxonase 2 Ser311Cys Polymorphism and Coronary Heart Disease Risk: A Meta-Analysis

Background

The relationship between coronary heart disease (CHD) and the paraoxonase 2 (PON2) Ser311Cys polymorphism has received much attention. We conducted a meta-analysis on the results from published case-control studies examining this relation.

Material/Methods

A literature search was performed using PubMed and ISI Web of Knowledge databases until October 2015. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using Stata version 11.0 software. Data were pooled using the random-effects model.

Results

Nine studies were eligible for statistical analysis and included a total of 5278 participants. The results did not support an association between the Ser311Cys polymorphism and CHD in the overall populations (Asians, Caucasians, and a Hispanic mixed population) under dominant (OR 1.07; 95% CI 0.91–1.28; P_z=0.413), recessive (OR 1.19; 95% CI 0.72–1.95; P_z=0.500), homozygote (OR 1.20; 95% CI 0.71–2.03; P_z=0.489), and allelic comparison (OR 1.08; 95% CI 0.91–1.28; P_z=0.390) models. However, in subgroup analysis according to ethnicity, we found that the Ser311Cys polymorphism was associated with CHD risk in Caucasians under recessive (OR 2.08; 95% CI 1.30–3.34; P_z=0.002) and homozygote (OR 2.16; 95% CI 1.33–3.50; P_z=0.002) models. Subgroup analysis indicated no significant association of this polymorphism with CHD in either Asian or Hispanic populations.

Conclusions

The PON2 Ser311Cys polymorphism is associated with CHD risk in Caucasians, but there is no association between this polymorphism and CHD in Asians or Hispanic populations.

A Guide for a Cardiovascular Genomics Biorepository: the CATHGEN Experience

The CATHeterization GENetics (CATHGEN) biorepository was assembled in four phases. First, project start-up began in 2000. Second, between 2001 and 2010, we collected clinical data and biological samples from 9334 individuals undergoing cardiac catheterization. Samples were matched at the individual level to clinical data collected at the time of catheterization and stored in the Duke Databank for Cardiovascular Diseases (DDCD). Clinical data included the following: subject demographics (birth date, race, gender, etc.); cardiometabolic history including symptoms; coronary anatomy and cardiac function at catheterization; and fasting chemistry data. Third, as part of the DDCD regular follow-up protocol, yearly evaluations included interim information: vital status (verified via National Death Index search and supplemented by Social Security Death Index search), myocardial infarction (MI), stroke, rehospitalization, coronary revascularization procedures, medication use, and lifestyle habits including smoking. Fourth, samples were used to generate molecular data. CATHGEN offers the opportunity to discover biomarkers and explore mechanisms of cardiovascular disease.

Novel epigenetic changes unveiled by monozygotic twins discordant for smoking habits

Exposure to cigarette smoking affects the epigenome and could increase the risk of developing diseases such as cancer and cardiovascular disorders. Changes in DNA methylation associated with smoking may help to identify molecular pathways that contribute to disease etiology. Previous studies are not completely concordant in the identification of differentially methylated regions in the DNA of smokers. We performed an epigenome-wide DNA methylation study in a group of monozygotic (MZ) twins discordant for smoking habits to determine the effect of smoking on DNA methylation. As MZ twins are considered genetically identical, this model allowed us to identify smoking-related DNA methylation changes independent from genetic components. We investigated the whole blood genome-wide DNA methylation profiles in 20 MZ twin pairs discordant for smoking habits by using the Illumina HumanMethylation450 BeadChip. We identified 22 CpG sites that were differentially methylated between smoker and non-smoker MZ twins by intra-pair analysis. We confirmed eight loci already described by other groups, located in AHRR, F2RL3, MYOG1 genes, at 2q37.1 and 6p21.33 regions, and also identified several new loci. Moreover, pathway analysis showed an enrichment of genes involved in GTPase regulatory activity. Our study confirmed the evidence of smoking-related DNA methylation changes, emphasizing that well-designed MZ twin models can aid the discovery of novel DNA methylation signals, even in a limited sample population.

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: χ(2) = 6.86; df = 2; P = 0.03; allele: χ(2) = 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.