Papers by Sucheta Vaingankar
Scientific Reports, 2020
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Scientific Reports, 2019
The intra-renal dopamine (DA) system is highly expressed in the proximal tubule and contributes t... more The intra-renal dopamine (DA) system is highly expressed in the proximal tubule and contributes to Na+ and blood pressure homeostasis, as well as to the development of nephropathy. In the kidney, the enzyme DOPA Decarboxylase (DDC) originating from the circulation. We used a twin/family study design, followed by polymorphism association analysis at DDC locus to elucidate heritable influences on renal DA production. Dense single nucleotide polymorphism (SNP) genotyping across the DDC locus on chromosome 7p12 was analyzed by re-sequencing guided by trait-associated genetic markers to discover the responsible genetic variation. We also characterized kinetics of the expressed DDC mutant enzyme. Systematic polymorphism screening across the 15-Exon DDC locus revealed a single coding variant in Exon-14 that was associated with DA excretion and multiple other renal traits indicating pleiotropy. When expressed and characterized in eukaryotic cells, the 462Gln variant displayed lower Vmax (ma...
BMC medical genetics, Jan 11, 2016
Plasma coagulation Factor XIIa (Hageman factor; encoded by F12) and kallikrein (KAL or Fletcher f... more Plasma coagulation Factor XIIa (Hageman factor; encoded by F12) and kallikrein (KAL or Fletcher factor; encoded by KLKB1) are proteases of the kallikerin-kinin system involved in converting the inactive circulating prorenin to renin. Renin is a key enzyme in the formation of angiotensin II, which regulates blood pressure, fluid and electrolyte balance and is a biomarker for cardiovascular, metabolic and renal function. The renin-angiotensin system is implicated in extinction learning in posttraumatic stress disorder. Active plasma renin was measured from two independent cohorts- civilian twins and siblings, as well as U.S. Marines, for a total of 1,180 subjects. Genotyping these subjects revealed that the carriers of the minor alleles at the two loci- F12 and KLKB1 had a significant association with reduced levels of active plasma renin. Meta-analyses confirmed the association across cohorts. In vitro studies verified digestion of human recombinant pro-renin by kallikrein (KAL) to g...
Journal of hypertension, Jan 7, 2015
The human prohormone chromogranin A (CHGA), an index member of the granin family is processed to ... more The human prohormone chromogranin A (CHGA), an index member of the granin family is processed to generate catestatin, a peptide that is hypotensive in action and modulates catecholamine release within the sympathoadrenal system. Hypertensive patients with excess sympathetic activity have diminished catestatin. Often the study of physiological consequences of human genetic variation is confounded by elements such as other variations in obligatory linkage disequilibrium with the variant being studied. Also the phenotype of the variant may be influenced by genetic background that varies amongst individuals. This study addresses the effects of a human catestatin polymorphism (rs9658667) using humanized CHGA mouse models. We created pertinent humanized mouse models wherein the mouse Chga gene locus was replaced by the human ortholog wild-type and the variant versions. This allowed for probing of the effects of catestatin variation in vivo with controls for other variations and global gen...
Anticancer research
The aim of the study was to investigate the immunohistochemical distribution of the novel neurope... more The aim of the study was to investigate the immunohistochemical distribution of the novel neuropeptide catestatin in carcinoid tumors. Catestatin, a novel 21 amino acid neuropeptide derived from chromogranin A, was determined immunohistochemically in 30 carcinoid tumors of the appendix and various carcinoid tumors of other localities. Paraffin-embedded tissues from 30 carcinoid tumors of the appendix and 16 other carcinoid tumors (5 bronchus-, 5 stomach-, 2 small bowel-, 4 large bowel carcinoid tumors) were incubated with antibodies specific for catestatin, chromogranin A and chromogranin B. Immunohistochemical staining of catestatin was compared to staining with chromogranin A and B. Western blot analysis was performed in one patient with ileal carcinoid. Thirty patients (20 women, 10 men) with carcinoid tumors of the appendix and 16 patients with other localized carcinoid tumors were investigated. Twenty-six of the appendiceal tumors were localized in the apex of the appendix and ...
Journal of Cardiovascular Translational Research, 2014
Journal of the American Society of Nephrology : JASN, Jan 12, 2014
Chromogranin A (CHGA) is coreleased with catecholamines from secretory vesicles in adrenal medull... more Chromogranin A (CHGA) is coreleased with catecholamines from secretory vesicles in adrenal medulla and sympathetic axons. Genetic variation in the CHGA 3'-region has been associated with autonomic control of circulation, hypertension, and hypertensive nephropathy, and the CHGA 3'-untranslated region (3'-UTR) variant C+87T (rs7610) displayed peak associations with these traits in humans. Here, we explored the molecular mechanisms underlying these associations. C+87T occurred in a microRNA-107 (miR-107) motif (match: T>C), and CHGA mRNA expression varied inversely with miR-107 abundance. In cells transfected with chimeric luciferase/CHGA 3'-UTR reporters encoding either the T allele or the C allele, changes in miR-107 expression levels had much greater effects on expression of the T allele. Cotransfection experiments with hsa-miR-107 oligonucleotides and eukaryotic CHGA plasmids produced similar results. Notably, an in vitro CHGA transcription/translation experiment...
Journal of the American College of Cardiology, 2008
We aimed to determine whether the common variation at the chromogranin A (CHGA) locus increases s... more 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 Ͼ1,000 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 Cϩ87T, accounting for up to ϳ12/ϳ9 mm Hg. The Cϩ87T genotype predicted CHGA secretion in vivo, with the ϩ87T allele (associated with lower BP) also diminishing plasma CHGA by ϳ10%. The Cϩ87T 3=-UTR variant also predicted the BP response to environmental (cold) stress; the same allele (ϩ87T) that diminished basal BP in the population also decreased the systolic BP response to stress by ϳ12 mm Hg, and the response was smaller in women (by ϳ6 mm Hg). In a chromaffin cell-transfected CHGA 3=-UTR/luciferase reporter plasmid, the ϩ87T allele associated with lower BP also decreased reporter expression by ϳ30%. 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 Cϩ87T 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.
Journal of Neurochemistry, 2013
CHGB is the major matrix protein in human catecholamine storage vesicles. CHGB genetic variation ... more CHGB is the major matrix protein in human catecholamine storage vesicles. CHGB genetic variation alters catecholamine secretion and blood pressure. Here effective Chgb protein underexpression was achieved by siRNA in PC12 cells, resulting in ~48% fewer secretory granules on EM, diminished capacity for catecholamine uptake (by ~79%), and a ~73% decline in stores available for nicotinic cholinergic-stimulated secretion. In vivo, loss of Chgb in knockout mice resulted in a ~35% decline in chromaffin granule abundance and ~44% decline in granule diameter, accompanied by unregulated catecholamine release into plasma. Over-expression of CHGB was achieved by transduction of a CHGB-expressing lentivirus, resulting in ~127% elevation in CHGB protein, with ~122% greater abundance of secretory granules, but only ~14% increased uptake of catecholamines, and no effect on nicotinic-triggered secretion. Human CHGB protein and its proteolytic fragments inhibited nicotinic-stimulated catecholamine release bỹ 72%. One conserved-region CHGB peptide inhibited nicotinic-triggered secretion by up tõ 41%, with partial blockade of cationic signal transduction. We conclude that bi-directional quantitative derangements in CHGB abundance result in profound changes in vesicular storage and release of catecholamines. When processed and released extra-cellularly, CHGB proteolytic fragments exert a feedback effect to inhibit catecholamine secretion, especially during nicotinic cholinergic stimulation.
Journal of Clinical Investigation, 2007
Journal of Clinical Investigation, 2005
The secretory prohormone chromogranin A (CHGA) is overexpressed in essential hypertension, a comp... more The secretory prohormone chromogranin A (CHGA) is overexpressed in essential hypertension, a complex trait with genetic predisposition, while its catecholamine release-inhibitory fragment catestatin is diminished, and low catestatin predicts augmented adrenergic pressor responses. These findings from studies on humans suggest a mechanism whereby diminished catestatin might increase the risk for hypertension. We generated Chga-/and humanized mice through transgenic insertion of a human CHGA haplotype in order to probe CHGA and catestatin in vivo. Chga-/mice displayed extreme phenotypic changes, including: (a) decreased chromaffin granule size and number; (b) elevated BP; (c) loss of diurnal BP variation; (d) increased left ventricular mass and cavity dimensions; (e) decreased adrenal catecholamine, neuropeptide Y (Npy), and ATP contents; (f) increased catecholamine/ATP ratio in the chromaffin granule; and (g) increased plasma catecholamine and Npy levels. Rescue of elevated BP to normalcy was achieved by either exogenous catestatin replacement or humanization of Chga-/mice. Loss of the physiological "brake" catestatin in Chga-/mice coupled with dysregulation of transmitter storage and release may act in concert to alter autonomic control of the circulation in vivo, eventuating in hypertension.
Journal of Biological Chemistry, 2009
Human Molecular Genetics, 2013
Endocrinology, 2008
The plasma level of chromogranin A (CgA) is elevated in genetic hypertension. Conversely, the pla... more The plasma level of chromogranin A (CgA) is elevated in genetic hypertension. Conversely, the plasma level of the CgA peptide catestatin is diminished in individuals with established hypertension and those with a genetic risk of this disease. Resequencing of the human CHGA gene identified three naturally occurring variants of catestatin (Gly364Ser, Pro370Leu, and Arg374Gln) that exhibit different potencies in inhibiting catecholamine secretion. Here, we have examined whether there is any differential processing of the three CHGA variants to catestatin by the endoproteolytic enzyme plasmin. Plasmin digestion of the purified CgA proteins generated a stable biologically active 14-amino acid peptide (human CgA360–373) from the wild-type, Gly364Ser, and Arg374Gln proteins despite the disruption of the dibasic site (Arg373Arg374) in the Arg374Gln variant. Unexpectedly, the action of plasmin in generating the catestatin peptide from the Pro370Leu protein was less efficient. The efficiency ...
Endocrinology, 2009
Chromogranin A (CgA), the major soluble protein in chromaffin granules, is proteolytically proces... more Chromogranin A (CgA), the major soluble protein in chromaffin granules, is proteolytically processed to generate biologically active peptides including the catecholamine release inhibitory peptide catestatin. Here we sought to determine whether cysteine protease cathepsin L (CTSL), a novel enzyme for proteolytic processing of neuropeptides, acts like the well-established serine proteases [prohormone convertase (PC)1/3 or PC2] to generate catestatin by proteolytic processing of CgA. We found that endogenous CTSL colocalizes with CgA in the secretory vesicles of primary rat chromaffin cells. Transfection of PC12 cells with an expression plasmid encoding CTSL directed expression of CTSL toward secretory vesicles. Deconvolution fluorescence microscopy suggested greater colocalization of CTSL with CgA than the lysosomal marker LGP110. The overexpression of CTSL in PC12 cells caused cleavage of full-length CgA. CTSL also cleaved CgA in vitro, in time- and dose-dependent fashion, and speci...
Current Hypertension Reports, 2010
Circulation: Cardiovascular Genetics, 2009
Background— Hypertension is a complex trait, with deranged autonomic control of circulation. Chro... more 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 ...
Circulation, 2007
Background— Chromogranin A, coreleased with catecholamines by exocytosis, is cleaved to the catec... more 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 h...
Cellular and Molecular Neurobiology, 2010
Biochemistry, 2007
Figure I. "123D" homology alignment results. "123D" alignment of wild-type mature (after signal p... more Figure I. "123D" homology alignment results. "123D" alignment of wild-type mature (after signal peptide excision) human CHGA (top half), from amino acids 48 through 349, with porcine cardiac alpha-tropomyosin (TPM1) amino acids 1-284 (bottom half). "H": 123D-algorithm-predicted alpha helices for CHGA, and known alpha helices for porcine tropomyosin (PDB 1c1g). Unlike direct (primary) sequence homology, this alignment also takes into account secondary structural homology. Note that there are matching alpha helical domains through most of the alignment. "E": predicted strand.
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Papers by Sucheta Vaingankar