| 1. |
- Salem, Rany M., et al.
(author)
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Chromogranin a polymorphisms are associated with hypertensive renal disease
- 2008
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In: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 19:3, s. 600-614
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Journal article (peer-reviewed)abstract
- Chromogranin A is released together with epinephrine and norepinephrine from catecholaminergic cells. Specific endopeptidases cleave chromogranin A into biologically active peptide fragments, including catestatin, which inhibits catecholamine release. Previous studies have suggested that a deficit in this sympathetic “braking” system might be an early event in the pathogenesis of human hypertension. Whether chromogranin A (CHGA) polymorphisms predict end-organ complications of hypertension, such as end-stage renal disease, is unknown. Among blacks, we studied common genetic variants spanning the CHGA locus in 2 independent case-control studies of hypertensive ESRD. Two haplotypes were significantly more frequent among subjects with hypertensive ESRD: 1) in the promoter (5′) region, G-462A→T-415C→C-89A, haplotype ATC (adjusted odds ratio = 2.65; P = 0.037), and 2) at the 3′-end, C11825T (3′-UTR, C+87T)→G12602C, haplotype TC (adjusted odds ratio = 2.73, P = 0.0196). Circulating levels of catestatin were lower among those with hypertensive ESRD than controls, an unexpected finding given that peptide levels are usually elevated in ESRD because of reduced renal elimination. We found that the 3′-UTR + 87T variant decreased reporter gene expression, providing a possible mechanistic explanation for diminished catestatin. In summary, common variants in chromogranin A associate with the risk of hypertensive ESRD in blacks.
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| 2. |
- Chen, Yuqing, et al.
(author)
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Naturally occurring human genetic variation in the 3'-untranslated region of the secretory protein chromogranin A is associated with autonomic blood pressure regulation and hypertension in a sex-dependent fashion
- 2008
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In: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 52:18, s. 1468-81
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Journal article (peer-reviewed)abstract
- OBJECTIVES: We aimed to determine whether the common variation at the chromogranin A (CHGA) locus increases susceptibility to hypertension. BACKGROUND: CHGA regulates catecholamine storage and release. Previously we systematically identified genetic variants across CHGA. METHODS: We carried out dense genotyping across the CHGA locus in >1,000 individuals with the most extreme blood pressures (BPs) in the population, as well as twin pairs with autonomic phenotypes. We also characterized the function of a trait-associated 3'-untranslated region (3'-UTR) variant with transfected CHGA 3'-UTR/luciferase reporter plasmids. RESULTS: CHGA was overexpressed in patients with hypertension, especially hypertensive men, and CHGA predicted catecholamines. In individuals with extreme BPs, CHGA genetic variants predicted BP, especially in men, with a peak association occurring in the 3'-UTR at C+87T, accounting for up to approximately 12/ approximately 9 mm Hg. The C+87T genotype predicted CHGA secretion in vivo, with the +87T allele (associated with lower BP) also diminishing plasma CHGA by approximately 10%. The C+87T 3'-UTR variant also predicted the BP response to environmental (cold) stress; the same allele (+87T) that diminished basal BP in the population also decreased the systolic BP response to stress by approximately 12 mm Hg, and the response was smaller in women (by approximately 6 mm Hg). In a chromaffin cell-transfected CHGA 3'-UTR/luciferase reporter plasmid, the +87T allele associated with lower BP also decreased reporter expression by approximately 30%. In cultured chromaffin cells, reducing endogenous CHGA expression by small interfering ribonucleic acid caused approximately two-thirds depletion of catecholamine storage vesicles. CONCLUSIONS: Common variant C+87T in the CHGA 3'-UTR is a functional polymorphism causally associated with hypertension especially in men of the population, and we propose steps ("intermediate phenotypes") whereby in a sex-dependent fashion this genetic variant influences the ultimate disease trait. These observations suggest new molecular strategies to probe the pathophysiology, risk, and rational treatment of hypertension.
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| 3. |
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| 4. |
- Rana, Brinda K., et al.
(author)
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Natural variation within the neuronal nicotinic acetylcholine receptor cluster on human chromosome 15q24 : influence on heritable autonomic traits in twin pairs
- 2009
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 331:2, s. 419-428
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Journal article (peer-reviewed)abstract
- Nicotinic acetylcholine receptors (nAChRs) are combinations of subunits arranged as pentamers encircling a central cation channel. At least nine α and four β subunits are expressed in the central and peripheral nervous systems; their presence in autonomic ganglia, the adrenal medulla, and central nervous system, with accompanying responses elicited by nicotinic agonists, point to their involvement in cardiovascular homeostasis. nAChRs formed by α3, α5, and β4 subunits may regulate blood pressure (BP) by mediating release of catestatin, the endogenous nicotinic antagonist fragment of chromogranin A (CHGA) and potent inhibitor of catecholamine secretion. Genes encoding these subunits (CHRNA3, CHRNA5, and CHRNB4) are clustered on human chromosome 15q24. Because variation in this cluster may alter autonomic regulation of BP, we sequenced ∼15 kilobase pairs in 15q24 containing their coding and 5′- and 3′-untranslated regions in 80 individuals. We identified 63 variants: 25 in coding regions of CHRNA3, CHRNA5, and CHRNB4 and 48 noncoding single-nucleotide polymorphisms (SNPs). Haplotype frequencies varied across ethnic populations. We assessed the contribution of six SNPs in the putative catestatin binding region of CHRNA3 and CHRNB4 to autonomic traits. In twins, catestatin and BP were heritable. CHRNA3 SNPs and haplotypes containing K95K (G285A) associated with circulating plasma catestatin, epinephrine levels, as well as systolic BP, suggesting altered coupling of the nAChRs to BP. Studies of chromaffin cells in vitro reveal that nicotinic agonist stimulation releases catecholamines and CHGA, a process augmented by overexpression of CHRNA3 and blocked by catestatin. These cellular events suggest a homeostatic mechanism underlying the pleiotropic actions of CHRNA3 genetic variation on autonomic function observed in twins.
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| 5. |
- Rao, Fangwen, et al.
(author)
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Catecholamine release-inhibitory peptide catestatin (chromogranin A352-372) : Naturally occurring amino acid variant Gly364Ser causes profound changes in human autonomic activity and alters risk for hypertension
- 2007
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In: Circulation. - 0009-7322 .- 1524-4539. ; 115:17, s. 2271-2281
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Journal article (peer-reviewed)abstract
- BACKGROUND - Chromogranin A, coreleased with catecholamines by exocytosis, is cleaved to the catecholamine release-inhibitory fragment catestatin. We identified a natural nonsynonymous variant of catestatin, Gly364Ser, that alters human autonomic function and blood pressure. METHODS AND RESULTS - Gly364Ser heterozygotes and controls underwent physiological and biochemical phenotyping, including catecholamine production, chromogranin A precursor, and its catestatin product. Case-control studies replicated effects of the gene on blood pressure in the population. Gly364Ser displayed diminished inhibition of catecholamine secretion from cultured neurons. Gly/Ser heterozygotes displayed increased baroreceptor slope during upward deflections (by ≈47%) and downward deflections (by ≈44%), increased cardiac parasympathetic index (by ≈2.4-fold), and decreased cardiac sympathetic index (by ≈26%). Renal norepinephrine excretion was diminished by ≈26% and epinephrine excretion by ≈34% in Gly/Ser heterozygotes. The coalescent dated emergence of the variant to ≈70 000 years ago. Gly364Ser was in linkage disequilibrium with 1 major Chromogranin A promoter haplotype, although promoter haplotypes did not predict autonomic phenotypes. The 364Ser variant was associated with lower diastolic blood pressure in 2 independent/confirmatory groups of patients with hypertension; genotype groups differed by ≈5 to 6 mm Hg, and the polymorphism accounted for ≈1.8% of population diastolic blood pressure variance, although a significant gene-by-sex interaction existed, with an enhanced effect in men. CONCLUSIONS - The catestatin Gly364Ser variant causes profound changes in human autonomic activity, both parasympathetic and sympathetic, and seems to reduce risk of developing hypertension, especially in men. A model for catestatin action in the baroreceptor center of the nucleus of the tractus solitarius accounts for these actions.
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| 6. |
- Wen, Gen, et al.
(author)
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An ancestral variant of Secretogranin II confers regulation by PHOX2 transcription factors and association with hypertension
- 2007
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In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 16:14, s. 1752-1764
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Journal article (peer-reviewed)abstract
- Granins regulate secretory vesicle formation in neuroendocrine cells and granin-derived peptides are co-released with neurotransmitters as modulatory signals at sympathetic sites. We report evidence for association between a regulatory polymorphism in Secretogranin II (SCG2) and hypertension in African-American subjects. The minor allele is ancestral in the human lineage and is associated with disease risk in two case-control studies and with elevated blood pressure in a separate familial study. Mechanistically, the ancestral allele acts as a transcriptional enhancer in cells that express endogenous Scg2, whereas the derived allele does not. ARIX (PHOX2A) and PHOX2B are identified as potential transactivating factors by oligonucleotide affinity chromatography and mass spectrometry and confirmed by chromatin immunoprecipitation. Each of these transcription factors preferentially binds the risk allele, both in vitro and in vivo. Population genetic considerations suggest positive selection of the protective allele within the human lineage. These results identify a common regulatory variation in SCG2 and implicate granin gene expression in the control of human blood pressure and susceptibility to hypertension.
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| 7. |
- Zhang, Kuixing, et al.
(author)
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Autonomic function in hypertension; role of genetic variation at the catecholamine storage vesicle protein chromogranin B
- 2009
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In: Circulation: Cardiovascular Genetics. - 1942-3268. ; 2:1, s. 46-56
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Journal article (peer-reviewed)abstract
- Background: Hypertension is a complex trait, with deranged autonomic control of circulation. Chromogranin B (CHGB) is the most abundant core protein in human catecholamine secretory vesicles, playing an important role in their biogenesis. Does common interindividual variation at the CHGB locus contribute to phenotypic variation in CHGB and catecholamine secretion, autonomic stability of circulation, or blood pressure (BP) in the population? Methods and Results: To probe interindividual variability in CHGB, we systematically studied polymorphism across the locus by resequencing CHGB (≈6 kbp footprint spanning the promoter, 5 exons, exon/intron borders, untranslated regions) in 160 subjects (2n=320 chromosomes) of diverse biogeographic ancestries. We identified 53 single-nucleotide polymorphisms, of which 22 were common. We then studied 1182 subjects drawn from the most extreme BP values in the population (highest and lowest 5th percentiles), typing 4 common polymorphisms spanning the ≈14 kbp locus. Sliding-window haplotype analysis indicated BP associations peaking in the 5'/promoter region, most prominent in men, and a peak effect in the proximal promoter at variant A-261T (A>T), accounting for ≈8/≈6 mm Hg BP in males. The promoter allele (A-261) that was a predictor of higher diastolic BP and systolic BP was also associated with lower circulating/plasma CHGB concentration (CHGB439to451 epitope) in twin pairs. In twins, the same CHGB variants that were predictors of lower basal CHGB secretion were also associated with exaggerated catecholamine secretion and BP response to environmental (cold) stress; likewise, women displayed increased plasma CHGB439to451 but decreased catecholamine secretion as well as BP response to environmental stress. The effect of A-261T on CHGB expression was confirmed in chromaffin cells by site-directed mutagenesis on transfected CHGB promoter/luciferase reporter activity, and the allelic effects of A-261T on gene expression were directionally coordinate in cella and in vivo. To confirm these clinical associations experimentally, we undertook targeted homozygous (-/-) ablation of the mouse CHGB gene; knockout mice displayed substantially increased BP, by ≈20/≈18 mm Hg, confirming the mechanistic basis of our findings in humans. Conclusion-Common genetic variation at the CHGB locus, especially in the proximal promoter, influences CHGB expression and later catecholamine secretion and the early heritable responses to environmental stress, eventuating in changes in resting/basal BP in the population. Both the early (gene expression) and late (population BP) consequences of CHGB variation are sex dependent. These results point to new molecular strategies for probing autonomic control of circulation and, ultimately, the susceptibility to and pathogenesis of cardiovascular disease states such as hypertension.
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