GNB3 gene 825 TT variant predicts hard coronary events in the population-based Heinz Nixdorf Recall study

Single-Nucleotide Polymorphism in Genes Encoding G Protein Subunits GNB3 and GNAQ Increase the Risk of Cardiovascular Morbidity among Patients Undergoing Renal Replacement Therapy

Single-nucleotide polymorphisms in G protein subunits are linked to an increased risk of cardiovascular events among the general population. We assessed the effects of GNB3 c.825C > T, GNAQ -695/-694GC > TT, and GNAS c.393C > T polymorphisms on the risk of cardiovascular events among 454 patients undergoing renal replacement therapy. The patients were followed up for a median of 4.5 years after the initiation of dialysis. Carriers of the TT/TT genotype of GNAQ required stenting because of coronary artery stenosis (p = 0.0009) and developed cardiovascular events involving more than one organ system (p = 0.03) significantly earlier and more frequently than did the GC/TT or GC/GC genotypes. Multivariate analysis found that the TT/TT genotype of GNAQ was an independent risk factor for coronary artery stenosis requiring stent (hazard ratio, 4.5; p = 0.001), cardiovascular events (hazard ratio, 1.93; p = 0.04) and cardiovascular events affecting multiple organs (hazard ratio, 4.9; p = 0.03). In the subgroup of male patients left ventricular dilatation with abnormally increased LVEDD values occurred significantly more frequently in TT genotypes of GNB3 than in CT/CC genotypes (p = 0.007). Our findings suggest that male dialysis patients carrying the TT genotype of GNB3 are at higher risk of left ventricular dilatation and that dialysis patients carrying the TT/TT genotype of GNAQ are prone to coronary artery stenosis and severe cardiovascular events.

GNB3 c.825C>T (rs5443) Polymorphism and Risk of Acute Cardiovascular Events after Renal Allograft Transplant

The c.825C>T single-nucleotide polymorphism (rs5443) of the guanine nucleotide-binding protein subunit β3 (GNB3) results in increased intracellular signal transduction via G-proteins. The present study investigated the effect of the GNB3 c.825C>T polymorphism on cardiovascular events among renal allograft recipients posttransplant. Our retrospective study involved 436 renal allograft recipients who were followed up for up to 8 years after transplant. The GNB3 c.825C>T polymorphism was detected with restriction fragment length polymorphism (RFLP) polymerase chain reaction (PCR). The GNB3 TT genotype was detected in 43 (10%) of 436 recipients. Death due to an acute cardiovascular event occurred more frequently among recipients with the TT genotype (4 [9%]) than among those with the CC/CT genotypes (7 [2%]; p = 0.003). The rates of myocardial infarction (MI)−free survival (p = 0.003) and acute peripheral artery occlusive disease (PAOD)−free survival (p = 0.004) were significantly lower among T-homozygous patients. A multivariate analysis showed that homozygous GNB3 c.825C>T polymorphism exerted only a mild effect for the occurrence of myocardial infarction (relative risk, 2.2; p = 0.065) or acute PAOD (relative risk, 2.4; p = 0.05) after renal transplant. Our results suggest that the homozygous GNB3 T allele exerts noticeable effects on the risk of MI and acute PAOD only in the presence of additional nonheritable risk factors.

Genetic variations in G-protein signal pathways influence progression of coronary artery calcification: Results from the Heinz Nixdorf Recall study

BACKGROUND AND AIMS

Coronary artery calcification (CAC) is one of the most sensitive and specific markers of coronary atherosclerosis and believed to be heritable. We hypothesized that functionally relevant single-nucleotide polymorphisms (SNPs) in the G-protein signal pathway, which have been previously related to coronary artery disease, are associated with CAC progression.

METHODS

3108 participants from the Heinz Nixdorf Recall study with CAC measurements at both baseline (CACb) and 5-year follow-up (CAC5y) were included. We genotyped SNPs rs1042714 (ADRB2), rs6026584 and rs12481583 (GNAS), and rs5443 (GNB3) and defined a priori risk alleles derived from literature data. Regression analyses were applied to measures of 5-year CAC progression, unadjusted, adjusted for age, sex, and adjusted for age, sex, log(CACb+1) as well as for cardiovascular risk factors.

RESULTS

The presence of one or more risk alleles was associated with a 26.9% (95% CI 5.5-52.4) increase in 5-year CAC progression (p = 0.011) and a 29.2% (95% CI 5.9-57.6) accelerated increase of CAC over the 5-year period compared to what was expected with respect to the baseline CAC percentile value (p = 0.012). Each of those risk alleles increased the 5-year CAC progression by 4.4% (95% CI 1.3-7.6, p = 0.006) and resulted in a 4.9% accelerated increase of CAC over the 5-year period (95% CI 1.6-8.4, p = 0.004). These unadjusted data did not change after adjustment.

CONCLUSIONS

Genetic variations in the G-protein signal pathway are associated with CAC progression in a cumulative fashion, indicating the importance of the pathway for genetic heritability in CAC progression and coronary artery disease.

Lack of association between the GNB3 rs5443, HIF1A rs11549465 polymorphisms, physiological and functional characteristics

The aim was to examine the association between the hypoxia-inducible factor-1α (HIF1A) gene and the guanine nucleotide binding protein beta polypeptide 3 (GNB3) gene polymorphisms and the endurance/power athlete status and relative aerobic capacity. Another goal of this study was to reveal the connection between GNB3, blood pressure (BP), body composition and body mass index (BMI). Two hundred thirty-eight people participated in this study: 148 elite athletes (men = 107, women = 41) and 90 controls (men = 51, women = 39). The athletes were divided into two groups: the power and the endurance athletes. BMI and body fat percentage (fat%) were calculated. Fifty of the athletes underwent an incremental treadmill test to exhaustion; BP was monitored before and after the test. There were differences in the genotype frequencies of HIF1A between the endurance and the control group (ProPro: 64% vs.79%, ProSer: 27% vs.19%, SerSer: 9% vs. 2%; p = .0351); in the allele prevalences among the three groups (Pro: 87% vs. 77% vs. 88%; Ser: 13% vs. 23% vs. 12%; p = .0103) and between the endurance and control group (p = .0049) as well. The GNB3 allele proportions differed in the three groups (C: 74% vs. 61% vs. 71%, T: 26% vs. 39% vs. 29%; p = .0436). There were no connections between the genotypes and the relative aerobic capacity and neither between GNB3 genotypes and BP, BMI and fat%. The connection of GNB3 T allele to the endurance performance still remained contradictable.

The Emerging Role of Gβ Subunits in Human Genetic Diseases

Environmental stimuli are perceived and transduced inside the cell through the activation of signaling pathways. One common type of cell signaling transduction network is initiated by G-proteins. G-proteins are activated by G-protein-coupled receptors (GPCRs) and transmit signals from hormones, neurotransmitters, and other signaling factors, thus controlling a number of biological processes that include synaptic transmission, visual photoreception, hormone and growth factors release, regulation of cell contraction and migration, as well as cell growth and differentiation. G-proteins mainly act as heterotrimeric complexes, composed of alpha, beta, and gamma subunits. In the last few years, whole exome sequencing and biochemical studies have shown causality of disease-causing variants in genes encoding G-proteins and human genetic diseases. This review focuses on the G-protein β subunits and their emerging role in the etiology of genetically inherited rare diseases in humans.

INSIG2 rs7566605 single nucleotide variant and global DNA methylation index levels are associated with weight loss in a personalized weight reduction program

Single nucleotide polymorphisms associated with lipid metabolism and energy balance are implicated in the weight loss response caused by nutritional interventions. Diet-induced weight loss is also associated with differential global DNA methylation. DNA methylation has been proposed as a predictive biomarker for weight loss response. Personalized biomarkers for successful weight loss may inform clinical decisions when deciding between behavioral and surgical weight loss interventions. The aim of the present study was to investigate the association between global DNA methylation, genetic variants associated with energy balance and lipid metabolism, and weight loss following a non-surgical weight loss regimen. The present study included 105 obese participants that were enrolled in a personalized weight loss program based on their allelic composition of the following five energy balance and lipid metabolism-associated loci: Near insulin-induced gene 2 (INSIG2); melanocortin 4 receptor; adrenoceptor β2; apolipoprotein A5; and G-protein subunit β3. The present study investigated the association between a global DNA methylation index (GDMI), the allelic composition of the five energy balance and lipid metabolism-associated loci, and weight loss during a 12 month program, after controlling for age, sex and body mass index (BMI). The results demonstrated a significant association between the GDMI and near INSIG2 locus, after adjusting for BMI and weight loss, and significant trends were observed when stratifying by gender. In conclusion, a combination of genetic and epigenetic biomarkers may be used to design personalized weight loss interventions, enabling adherence and ensuring improved outcomes for obesity treatment programs. Precision weight loss programs designed based on molecular information may enable the creation of personalized interventions for patients, that use genomic biomarkers for treatment design and for treatment adherence monitoring, thus improving response to treatment.

Association of G-protein beta3 subunit gene C825T polymorphism with cardiac and cerebrovascular events in Chinese hypertensive patients

Several recent studies showed that C825T polymorphism is related to cardiovascular diseases in normal population. However, studies on whether 825T allele influences the incidence of cardiovascular diseases in hypertensive patients are rare. In the current study, 729 patients (CC, n = 332; CT, n = 313; TT, n = 84) with essential hypertension were genotyped for C825T polymorphism of the GNB3 gene and followed 8 years for major adverse cardiovascular events (MACEs) which include stroke, the onset of coronary artery disease (CAD), and all-cause death. Established cardiovascular risk factors were used to adjust the multivariate Cox analysis. After a mean follow-up period of 7.60 ± 1.12 years, a significantly higher incidence of MACEs was seen in the TT genotype group than CC and CT genotypes. The TT variant was significantly and independently predictive of MACEs (relative risk = 2.574; p < 0.001), CAD (relative risk = 2.963; p < 0.001), but not stroke, CAD+stroke or death. The GNB3 TT genotype is a risk factor for CAD independent of other established cardiovascular risk factors in Chinese hypertensive patients.

Cardiovascular diseases-related GNB3 C825T polymorphism has a significant sex-specific effect on serum soluble E-selectin levels

Background

The C825T polymorphism (rs5443) of the Guanine Nucleotide-Binding protein subunit β3 (GNB3) gene has been associated with obesity, essential hypertension, atherosclerosis, coronary diseases, and cerebrovascular events, but with some sex-specific effects. Its association with inflammatory mediators such as cell adhesion molecules has not been studied, although they are heavily involved in cardiovascular diseases’ (CVDs) processes. The aim of our study was then to investigate a possible sex-specific effect of the GNB3 C825T polymorphism on serum soluble cell adhesion molecules such as E, P and L-selectins (sE, sP and sL-selectins).

Results

Participants were from the STANISLAS Family Study and were free of chronic disease as CVDs or cancer. We included in total 771 subjects aged 6 to 58 years (391 males (50.71%) and 380 females (49.29%)). No significant association of rs5443 was observed in the whole population with serum sE, sP and sL-selectins after adjusting for age, sex, body mass index, systolic blood pressure, anti-inflammatory drugs and hormonal drugs consumption. A significant interaction of rs5443 was observed with sex for sE-selectin (p < 0.001), but not for sP and sL-selectins. After adjusting for covariables, the T allele was significantly associated with an additive increase effect on serum sE-selectin levels in males (β = 5.03 ± 2.18; p = 0.020), while a significant additive decrease effect was observed in females (β =−4.46 ± 2.06; p = 0.030). These associations stayed significant after correction for multiple tests (p = 0.045 in males and in females). The additive phenotypic variance was 21.54% in males versus 1.91% in females.

Conclusions

In our Caucasian population, the GNB3 C825T polymorphism showed a significant sex-specific effect on serum sE-selectin levels, with a disadvantage for males, as increased sE-selectin levels has been associated with CVDs outcomes. The T allele has been previously associated with the same CVDs as increased sE-selectin, but more often in males. The link we observed between this polymorphism and E-selectin is then consistent with previous findings, and helps to better understand the deleterious effect of the GNB3 825 T allele on CVDs outcomes in males. We revealed in this study an important pathway through which the GNB3 gene induces CVDs’ outcomes.

G-Protein β3-Subunit Gene C825T Polymorphism and Cardiovascular Risk: An Updated Review

Hypertension is a common disorder of multifactorial origin that constitutes a major risk factor for cardiovascular events such as stroke and myocardial infarction. The subunits of the heterotrimeric G proteins are attractive candidate gene products for susceptibility to hypertension, obesity and insulin resistance syndrome. A polymorphism (825C/T) in exon 10 of the GNB3 gene, encoding for the Gβ3 subunit, has been described. The 825T allele is associated with alternative splicing of the gene and formation of a truncated but functionally active β3 subunit. Many studies have investigated whether carriers of the 825T allele are at increased risk for hypertension, obesity, insulin-resistance and left ventricular hypertrophy with apparently conflicting results. The present review demonstrates that GNB3 825T allele is a useful genetic marker for better defining the risk profile of hypertensive patients, as it is associated with increased risk of stroke and myocardial infarction in longitudinal studies in Caucasians.