Association of novel promoter single nucleotide polymorphisms in vasopressin V1a receptor gene with essential hypertension in nonobese Japanese

The AVPR1A Gene and Its Single Nucleotide Polymorphism rs10877969: A Literature Review of Associations with Health Conditions and Pain

BACKGROUND

Pain is the quintessential symptom for individuals suffering from sickle cell disease (SCD). Although the degree of suffering and the cost of treatment are staggering, SCD continues to be grossly understudied, including a lack of data for pain-related genes and prevalence of polymorphisms in this population. This lack of data adds to the inadequacy of pain therapy in this population. Pain genetics investigators have recently examined allele frequencies of single-nucleotide polymorphisms from candidate genes in people who have SCD. One of the genes identified was the arginine vasopressin receptor 1A gene (AVPR1A) and its associated single-nucleotide polymorphism (SNP) rs10877969. Progress in explaining pain-related polymorphisms associated with SCD can be facilitated by understanding the literature. Aim/Design: The purpose of this literature review was to describe mechanisms of the polymorphic gene AVPR1A and the phenotypic variations associated with its SNPs relative to health conditions and pain.

METHODS

Published studies were included if the research addressed AVPR1A and was a full article in a peer-reviewed journal, in the English language, a human or animal study, and published 2009 to present. Abstracts were included if they were in English and provided information not found in a full article.

RESULTS

The results of this review revealed that AVPR1A is associated with behavioral phenotypes, which include pair bonding, autism spectrum disorder, musical aptitude, infidelity, altruism, monogamy, mating, substance abuse, and alcohol preference. In addition, there were associations with pain, stress pain by sex, and sickle cell pain.

CONCLUSION

Summary of this literature could provide insights into future pain research of this SNP in people with SCD.

Lack of association of mirSNP rs11174811 in AVPR1A gene with arterial blood pressure and hypertension in South Indian population

Epigenetic regulation of arterial blood pressure mediated through mirSNPs in renin-angiotensin aldosterone system (RAAS) genes is a less explored hypothesis. Recently, the mirSNP rs11174811 in the 3'UTR of the AVPR1A gene was associated with higher arterial blood pressure in a large study population from the Study of Myocardial Infarctions Leiden (SMILE). The aim of the present study was to replicate the association of mirSNP rs11174811 with blood pressure outcomes and hypertension in a south Indian population. Four hundred and fifteen hypertensive cases and 416 normotensive controls were genotyped using a 5' nuclease allelic discrimination assay. Logistic regression was used to test the association of mirSNP rs11174811 with the hypertension phenotype. Censored normal regression was used to test the association of the polymorphism with continuous blood pressure outcomes such as systolic and diastolic blood pressure. The mirSNP rs11174811 did not show any significant association with hypertension. The adjusted odds ratio was 1.02, with 95% CI of 0.72 to 1.45 (p = 0.909). The mean systolic and diastolic blood pressure values were not significantly different across the three genotypic groups, between hypertensives and normotensives, or when stratified by gender. Despite having a similar minor allele frequency (MAF) of 14.5% compared with the SMILE cohort, our results did not support an association of the mirSNP rs11174811 with the hypertension phenotype or with continuous blood pressure outcomes in the south Indian population.

Short article: Impact of genetic variation in the vasopressin 1a receptor on the development of organ failure in patients admitted for acute decompensation of liver cirrhosis

BACKGROUND

Vasopressin receptor-mediated vasoconstriction is considered to be involved in the pathogenesis of organ failure in acute-on-chronic liver failure (ACLF).

PATIENTS AND METHODS

We studied the association between six single nucleotide polymorphisms (SNPs) of the vasopressin 1a receptor gene and the development of organ failure in 826 patients admitted for acute decompensation of liver cirrhosis (n=641) or ACLF (n=185).

RESULTS

No associations were found for SNPs with the presence of circulatory or renal failure. A C>T mutation in SNP rs7308855 and a T>A mutation in SNP rs7298346 showed an association with the presence of coagulation failure in the entire population (n=61, P=0.024 and 0.060, respectively) and in the subgroup of patients with ACLF (n=44, P=0.081 and 0.056, respectively).

CONCLUSION

Genetic variation in the vasopressin 1a receptor was found not to be associated with circulatory or renal failure, but with the presence of coagulation failure in patients with acute decompensation of liver cirrhosis and ACLF.

Tyrosine hydroxylase polymorphism (C-824T) and hypertension: a population-based study

BACKGROUND

Sympathetic nervous system (SNS) overactivity is present in a large proportion of the hypertensive population and precedes the development of established hypertension. Variations in the proximal promoter of the tyrosine hydroxylase (TH) gene have been shown to influence biochemical and physiological traits in the SNS as well as hypertension.

METHODS

We investigated the relationship between a common single-nucleotide polymorphism (SNP) in the proximal TH promoter (C-824T) and blood pressure (BP) in a large general population sample, characterized by 24-h ambulatory BP (ABP) monitoring and office BP measurement.

RESULTS

The study population consisted of 1,221 women and 1,182 men, ages 41-71 years, without major cardiovascular diseases. Regarding the C-824T SNP, 32.4% had the C/C genotype, 50.0% the C/T genotype, and 17.6% the T/T genotype. The T/T genotype conferred an ~45% increase in relative risk of hypertension, defined by conventional criteria, compared with the C/C genotype, and participants with the T/T genotype had significantly higher mean (95% confidence interval (CI)) systolic BP (SBP) (138 (136-140) mm Hg vs. 135 (133-136)), diastolic BP (DBP) (88 (86-89) mm Hg vs. 85 (84-86)), and heart rate (68 (67-69) beats/min vs. 66 (65-67)) than participants with the C/C genotype (P < 0.05). BP, heart rate, and prevalence of hypertension were intermediate in participants with the C/T genotype. These effects were the same in women and men and whether BP was measured in the office or by 24-h ambulatory monitoring.

CONCLUSION

The C-824T SNP in the proximal TH promoter influences BP and prevalence of hypertension in the general population.

A common single nucleotide polymorphism alters the synthesis and secretion of neuropeptide Y

A single nucleotide polymorphism (SNP) in the neuropeptide Y gene has been associated with elevated serum lipid levels and cardiovascular disease. The polymorphism (T1128C) changes the seventh amino acid in the prohormone from leucine to proline. It has been speculated this alters neuropeptide Y (NPY) synthesis, trafficking, or secretion. We tested this hypothesis by expressing the mutant and wild-type prohormones in CNS neurons and endocrine cells. Synthesis and trafficking were followed using immunocytochemistry and fluorescent protein-tagged fusion constructs. Mutant prohormone was synthesized and entered the regulated secretory pathway. When expressed in endocrine cells, wild-type and mutant proteins were found in the same large dense core granules. However, the T1128C polymorphism altered the degree of copackaging, and, on average, individual granules contained more mutant prohormone. This was not attributable to codon bias but to the change in prohormone sequence. Global prohormone targeting was normal, because in hippocampal neurons, the polarized distribution of the mutant prohormone was indistinguishable from the wild-type. When secretion was measured from chromaffin cells, brief depolarizations triggered peptide secretion, confirming the entry of the mutant prohormone into the regulated secretory pathway. However, cells that expressed the mutant protein had increased levels of peptide secretion. We conclude that the T1128C polymorphism alters the packaging and secretion of NPY. In contrast to SNPs in other prohormones, we could not find a phenotype until the prohormone was tracked at the single granule level. These results are consistent with studies showing the T1128C polymorphism has pleiotropic effects.