scholarly journals DNA Methylation of the Angiotensinogen Gene, AGT, and the Aldosterone Synthase Gene, CYP11B2 in Cardiovascular Diseases

2021 ◽  
Vol 22 (9) ◽  
pp. 4587
Author(s):  
Yoshimichi Takeda ◽  
Masashi Demura ◽  
Takashi Yoneda ◽  
Yoshiyu Takeda
Keyword(s):  
Dna Methylation ◽  
Angiotensin Ii ◽  
Cardiovascular Diseases ◽  
Salt Intake ◽  
Binding Protein ◽  
Close Association ◽  
Dna Demethylation ◽  
Dna Hypomethylation ◽  
Aldosterone Synthase ◽  
High Salt Intake

Angiotensinogen (AGT) and aldosterone play key roles in the regulation of blood pressure and are implicated in the pathogenesis of cardiovascular diseases. DNA methylation typically acts to repress gene transcription. The aldosterone synthase gene CYP11B2 is regulated by angiotensin II and potassium. DNA methylation negatively regulates AGT and CYP11B2 expression and dynamically changes in response to continuous promoter stimulation of each gene. High salt intake and excess circulating aldosterone cause DNA demethylation around the CCAAT-enhancer-binding-protein (CEBP) sites of the CYP11B2 promoter region, thereby converting the phenotype of AGT expression from an inactive to an active state in visceral adipose tissue and heart. A close association exists between low DNA methylation at CEBP-binding sites and increased AGT expression in salt-sensitive hypertensive rats. Salt-dependent hypertension may be partially affected by increased cardiac AGT expression. CpG dinucleotides in the CYP11B2 promoter are hypomethylated in aldosterone-producing adenomas. Methylation of recognition sequences of transcription factors, including CREB1, NGFIB (NR4A1), and NURR1 (NR4A2) diminish their DNA-binding activity. The methylated CpG-binding protein MECP2 interacts directly with the methylated CYP11B2 promoter. Low salt intake and angiotensin II infusion lead to upregulation of CYP11B2 expression and DNA hypomethylation in the adrenal gland. Treatment with the angiotensin II type 1 receptor antagonist decreases CYP11B2 expression and leads to DNA hypermethylation. A close association between low DNA methylation and increased CYP11B2 expression are seen in the hearts of patients with hypertrophic cardiomyopathy. These results indicate that epigenetic regulation of both AGT and CYP11B2 contribute to the pathogenesis of cardiovascular diseases.

Hemodynamics, fluid volume, and hormonal responses to chronic high-salt intake in dogs

1990 ◽  
Vol 259 (6) ◽  
pp. H1629-H1636 ◽  
Author(s):  
J. E. Krieger ◽  
J. F. Liard ◽  
A. W. Cowley
Keyword(s):  
Angiotensin Ii ◽  
Salt Intake ◽  
Peripheral Resistance ◽  
Plasma Renin ◽  
Total Body Weight ◽  
High Salt ◽  
Plasma Sodium ◽  
Plasma Protein Concentration ◽  
Hormonal Responses ◽  
High Salt Intake

The sequential hemodynamics, fluid and electrolyte balances, and the hormonal responses to a 7-day high-salt (NaCl) intake were investigated in sodium-depleted conscious dogs (n = 6). Studies were carried out in metabolic cages mounted on sensitive load cells, which enabled continuous 24 h/day monitoring of total body weight (TBW) as an index of changes in body water. Beat-by-beat hemodynamics were determined 24 h/day. Water (700 ml/day iv) intake was maintained constant. Daily fluid and electrolyte balances and hormonal analyses were performed. An increase of daily salt intake from 8 to 120 meq increased TBW 251 +/- 44 g (P less than 0.05), which was sustained thereafter. Average 24-h mean arterial pressure (MAP) and heart rate (HR) remained unchanged. Average cardiac output (CO) increased 11% (P less than 0.05) above control values by day 2, while total peripheral resistance (TPR) decreased proportionally. CO and TPR returned to control values only when low salt was resumed. Blood volume (BV) was unchanged on day 2 as indicated by direct measurement of BV (51Cr-labeled red blood cells) or by analysis of plasma protein concentration. A 92-meq (P less than 0.05) sodium retention was observed initially, and plasma sodium concentration increased slightly. Plasma renin activity, angiotensin II, and aldosterone levels decreased significantly, whereas vasopressin and atrial natriuretic peptide levels remained unchanged. In summary, chronic high-salt intake resulted in a net retention of water and sodium with no changes in MAP, HR, or BV. The rise in CO was offset by a reduction in TPR, which appeared at least in part related to angiotensin II suppression.

scholarly journals Central and peripheral slow-pressor mechanisms contributing to Angiotensin II-salt hypertension in rats

2017 ◽  
Vol 114 (2) ◽  
pp. 233-246 ◽  
Author(s):  
Jiao Lu ◽  
Hong-Wei Wang ◽  
Monir Ahmad ◽  
Marzieh Keshtkar-Jahromi ◽  
Mordecai P Blaustein ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Adrenal Cortex ◽  
Salt Intake ◽  
Plasma Corticosterone ◽  
High Salt ◽  
Ang Ii ◽  
Intracerebroventricular Infusion ◽  
High Salt Intake ◽  
Endogenous Ouabain ◽  
Salt Hypertension

AbstractAimsHigh salt intake markedly enhances hypertension induced by angiotensin II (Ang II). We explored central and peripheral slow-pressor mechanisms which may be activated by Ang II and salt.Methods and resultsIn protocol I, Wistar rats were infused subcutaneously with low-dose Ang II (150 ng/kg/min) and fed regular (0.4%) or high salt (2%) diet for 14 days. In protocol II, Ang II-high salt was combined with intracerebroventricular infusion of mineralocorticoid receptor (MR) blockers (eplerenone, spironolactone), epithelial sodium channel (ENaC) blocker (benzamil), angiotensin II type 1 receptor (AT1R) blocker (losartan) or vehicles. Ang II alone raised mean arterial pressure (MAP) ∼10 mmHg, but Ang II-high salt increased MAP ∼50 mmHg. Ang II-high salt elevated plasma corticosterone, aldosterone and endogenous ouabain but not Ang II alone. Both Ang II alone and Ang II-high salt increased mRNA and protein expression of CYP11B2 (aldosterone synthase gene) in the adrenal cortex but not of CYP11B1 (11-β-hydroxylase gene). In the aorta, Ang II-high salt increased sodium-calcium exchanger-1 (NCX1) protein. The Ang II-high salt induced increase in MAP was largely prevented by central infusion of MR blockers, benzamil or losartan. Central blockades significantly lowered plasma aldosterone and endogenous ouabain and markedly decreased Ang II-high salt induced CYP11B2 mRNA expression in the adrenal cortex and NCX1 protein in the aorta.ConclusionThese results suggest that in Ang II-high salt hypertension, MR-ENaC-AT1R signalling in the brain increases circulating aldosterone and endogenous ouabain, and arterial NCX1. These factors can amplify blood pressure responses to centrally-induced sympatho-excitation and thereby contribute to severe hypertension.

scholarly journals Role of central nervous system aldosterone synthase and mineralocorticoid receptors in salt-induced hypertension in Dahl salt-sensitive rats

2009 ◽  
Vol 296 (4) ◽  
pp. R994-R1000 ◽  
Author(s):  
Bing S. Huang ◽  
Roselyn A. White ◽  
Arco Y. Jeng ◽  
Frans H. H. Leenen
Keyword(s):  
Salt Intake ◽  
High Salt ◽  
High Salt Diet ◽  
Salt Diet ◽  
Aldosterone Synthase ◽  
High Salt Intake ◽  
Induced Hypertension ◽  
Synthase Inhibitor ◽  
The Brain

In Dahl salt-sensitive (S) rats, high salt intake increases cerebrospinal fluid (CSF) Na+ concentration ([Na+]) and blood pressure (BP). Intracerebroventricular (ICV) infusion of a mineralocorticoid receptor (MR) blocker prevents the hypertension. To assess the role of aldosterone locally produced in the brain, we evaluated the effects of chronic central blockade with the aldosterone synthase inhibitor FAD286 and the MR blocker spironolactone on changes in aldosterone and corticosterone content in the hypothalamus and the increase in CSF [Na+] and hypertension induced by high salt intake in Dahl S rats. After 4 wk of high salt intake, plasma aldosterone and corticosterone were not changed, but hypothalamic aldosterone increased by ∼35% and corticosterone tended to increase in Dahl S rats, whereas both steroids decreased by ∼65% in Dahl salt-resistant rats. In Dahl S rats fed the high-salt diet, ICV infusion of FAD286 or spironolactone did not affect the increase in CSF [Na+]. ICV infusion of FAD286 prevented the increase in hypothalamic aldosterone and 30 mmHg of the 50-mmHg BP increase induced by high salt intake. ICV infusion of spironolactone fully prevented the salt-induced hypertension. These results suggest that, in Dahl S rats, high salt intake increases aldosterone synthesis in the hypothalamus and aldosterone acts as the main MR agonist activating central pathways contributing to salt-induced hypertension.

scholarly journals High-Salt Intake Induces Cardiomyocyte Hypertrophy in Rats in Response to Local Angiotensin II Type 1 Receptor Activation

2014 ◽  
Vol 144 (10) ◽  
pp. 1571-1578 ◽  
Author(s):  
Isis A. Katayama ◽  
Rafael C. Pereira ◽  
Ellen P. B. Dopona ◽  
Maria H. M. Shimizu ◽  
Luzia N. S. Furukawa ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Salt Intake ◽  
Receptor Activation ◽  
High Salt ◽  
Cardiomyocyte Hypertrophy ◽  
High Salt Intake

scholarly journals Reprogramming of DNA methylation at NEUROD2-bound sequences during cortical neuron differentiation

2019 ◽  
Vol 5 (10) ◽  
pp. eaax0080 ◽  
Author(s):  
Maria A. Hahn ◽  
Seung-Gi Jin ◽  
Arthur X. Li ◽  
Jiancheng Liu ◽  
Zhijun Huang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Binding Sites ◽  
Bisulfite Sequencing ◽  
Dna Demethylation ◽  
Whole Genome ◽  
Dna Hypomethylation ◽  
Embryonic Neurogenesis ◽  
Genome Bisulfite Sequencing ◽  
Developing Neurons

The characteristics of DNA methylation changes that occur during neurogenesis in vivo remain unknown. We used whole-genome bisulfite sequencing to quantitate DNA cytosine modifications in differentiating neurons and their progenitors isolated from mouse brain at the peak of embryonic neurogenesis. Localized DNA hypomethylation was much more common than hypermethylation and often occurred at putative enhancers within genes that were upregulated in neurons and encoded proteins crucial for neuronal differentiation. The hypomethylated regions strongly overlapped with mapped binding sites of the key neuronal transcription factor NEUROD2. The 5-methylcytosine oxidase ten-eleven translocation 2 (TET2) interacted with NEUROD2, and its reaction product 5-hydroxymethylcytosine accumulated at the demethylated regions. NEUROD2-targeted differentially methylated regions retained higher methylation levels in Neurod2 knockout mice, and inducible expression of NEUROD2 caused TET2-associated demethylation at its in vivo binding sites. The data suggest that the reorganization of DNA methylation in developing neurons involves NEUROD2 and TET2-mediated DNA demethylation.

scholarly journals Paradoxical association of TET loss of function with genome-wide DNA hypomethylation

2019 ◽  
Vol 116 (34) ◽  
pp. 16933-16942 ◽  
Author(s):  
Isaac F. López-Moyado ◽  
Ageliki Tsagaratou ◽  
Hiroshi Yuita ◽  
Hyungseok Seo ◽  
Benjamin Delatte ◽  
...  
Keyword(s):  
Dna Methylation ◽  
T Cells ◽  
Genomic Analysis ◽  
Dna Demethylation ◽  
Potential Contribution ◽  
Loss Of Function ◽  
Dna Hypomethylation ◽  
Dna Hypermethylation ◽  
Hematopoietic Stem ◽  
Cancer Genomes

Cancer genomes are characterized by focal increases in DNA methylation, co-occurring with widespread hypomethylation. Here, we show that TET loss of function results in a similar genomic footprint. Both 5hmC in wild-type (WT) genomes and DNA hypermethylation in TET-deficient genomes are largely confined to the active euchromatic compartment, consistent with the known functions of TET proteins in DNA demethylation and the known distribution of 5hmC at transcribed genes and active enhancers. In contrast, an unexpected DNA hypomethylation noted in multiple TET-deficient genomes is primarily observed in the heterochromatin compartment. In a mouse model of T cell lymphoma driven by TET deficiency (Tet2/3 DKO T cells), genomic analysis of malignant T cells revealed DNA hypomethylation in the heterochromatic genomic compartment, as well as reactivation of repeat elements and enrichment for single-nucleotide alterations, primarily in heterochromatic regions of the genome. Moreover, hematopoietic stem/precursor cells (HSPCs) doubly deficient for Tet2 and Dnmt3a displayed greater losses of DNA methylation than HSPCs singly deficient for Tet2 or Dnmt3a alone, potentially explaining the unexpected synergy between DNMT3A and TET2 mutations in myeloid and lymphoid malignancies. Tet1-deficient cells showed decreased localization of DNMT3A in the heterochromatin compartment compared with WT cells, pointing to a functional interaction between TET and DNMT proteins and providing a potential explanation for the hypomethylation observed in TET-deficient genomes. Our data suggest that TET loss of function may at least partially underlie the characteristic pattern of global hypomethylation coupled to regional hypermethylation observed in diverse cancer genomes, and highlight the potential contribution of heterochromatin hypomethylation to oncogenesis.

Renal angiotensin II concentration and interstitial infiltration of immune cells are correlated with blood pressure levels in salt-sensitive hypertension

2007 ◽  
Vol 293 (1) ◽  
pp. R251-R256 ◽  
Author(s):  
Martha Franco ◽  
Flavio Martínez ◽  
Yasmir Quiroz ◽  
Othir Galicia ◽  
Rocio Bautista ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Immune Cell ◽  
Salt Intake ◽  
Experimental Models ◽  
High Salt ◽  
Salt Diet ◽  
High Salt Intake ◽  
Plasma Angiotensin ◽  
Salt Sensitive Hypertension

Renal immune cell infiltration and cells expressing angiotensin II (AII) in tubulointerstitial areas of the kidney are features of experimental models of salt-sensitive hypertension (SSHTN). A high-salt intake tends to suppress circulating AII levels, but intrarenal concentrations of AII have not been investigated in SSHTN. This study explored the relationship between these features to gain insight into the pathophysiology of SSHTN. Plasma angiotensin II (AII) and renal interstitial AII (microdialysis technique) and the infiltration of macrophages, lymphocytes, and AII-positive cells were determined in SSHTN induced by 5 wk of a high-salt diet (HSD) after short-term infusion of AII in rats with ( n = 10) and without ( n = 11) treatment with mycophenolate mofetil (MMF) and in control rats fed a high- ( n = 7) and normal ( n = 11) salt diet. As in previous studies, MMF did not affect AII-associated hypertension but reduced the interstitial inflammation and the SSHTN in the post-AII-period. During the HSD period, the AII group untreated with MMF had mean ± SD) low plasma (2.4 ± 1.4 pg/ml) and high interstitial AII concentration (1,310 ± 208 pg/ml); MMF treatment resulted in a significantly lower interstitial AII (454 ± 128 pg/ml). Renal AII concentration and the number of tubulointerstitial AII-positive cells were correlated. Blood pressure correlated positively with interstitial AII and negatively with plasma AII, thus giving compelling evidence of the paramount role of the AII within the kidney in the AII-induced model of salt-driven hypertension.

Links Between Dietary Salt Intake, Renal Salt Handling, Blood Pressure, and Cardiovascular Diseases

2005 ◽  
Vol 85 (2) ◽  
pp. 679-715 ◽  
Author(s):  
Pierre Meneton ◽  
Xavier Jeunemaitre ◽  
Hugh E. de Wardener ◽  
Graham A. Macgregor
Keyword(s):  
Blood Pressure ◽  
Cardiovascular Diseases ◽  
Salt Intake ◽  
Causal Link ◽  
Left Ventricular ◽  
High Salt ◽  
Human Populations ◽  
Dietary Salt ◽  
Dietary Salt Intake ◽  
High Salt Intake

Epidemiological, migration, intervention, and genetic studies in humans and animals provide very strong evidence of a causal link between high salt intake and high blood pressure. The mechanisms by which dietary salt increases arterial pressure are not fully understood, but they seem related to the inability of the kidneys to excrete large amounts of salt. From an evolutionary viewpoint, the human species is adapted to ingest and excrete <1 g of salt per day, at least 10 times less than the average values currently observed in industrialized and urbanized countries. Independent of the rise in blood pressure, dietary salt also increases cardiac left ventricular mass, arterial thickness and stiffness, the incidence of strokes, and the severity of cardiac failure. Thus chronic exposure to a high-salt diet appears to be a major factor involved in the frequent occurrence of hypertension and cardiovascular diseases in human populations.

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