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Chronic Diseases and Translational... Jun 2024Hypertension (HTN) involves genetic variability in the renin-angiotensin system and influences antihypertensive response. We previously reported that angiotensinogen ()...
BACKGROUND
Hypertension (HTN) involves genetic variability in the renin-angiotensin system and influences antihypertensive response. We previously reported that angiotensinogen () messenger RNA (mRNA) is endogenously bound by miR-122-5p and rs699 A > G decreases reporter mRNA in the microRNA functional-assay PASSPORT-seq. The promoter variant rs5051 C > T is in linkage disequilibrium (LD) with rs699 A > G and increases transcription. The independent effect of these variants is understudied due to their LD therefore we aimed to test the hypothesis that increased by rs5051 C > T counterbalances decreased by rs699 A > G, and when these variants occur independently, it translates to HTN-related phenotypes.
METHODS
We used in silico, in vitro, in vivo, and retrospective models to test this hypothesis.
RESULTS
In silico, rs699 A > G is predicted to increase miR-122-5p binding affinity by 3%. Mir-eCLIP results show rs699 is 40-45 nucleotides from the strongest microRNA-binding site in the mRNA. Unexpectedly, rs699 A > G increases mRNA in an -plasmid-cDNA HepG2 expression model. Genotype-Tissue Expression (GTEx) and UK Biobank analyses demonstrate liver expression and HTN phenotypes are not different when rs699 A > G occurs independently from rs5051 C > T. However, GTEx and the in vitro experiments suggest rs699 A > G confers cell-type-specific effects on mRNA abundance, and suggest paracrine renal renin-angiotensin-system perturbations could mediate the rs699 A > G associations with HTN.
CONCLUSIONS
We found that rs5051 C > T and rs699 A > G significantly associate with systolic blood pressure in Black participants in the UK Biobank, demonstrating a fourfold larger effect than in White participants. Further studies are warranted to determine if altered antihypertensive response in Black individuals might be due to rs5051 C > T or rs699 A > G. Studies like this will help clinicians move beyond the use of race as a surrogate for genotype.
PubMed: 38872760
DOI: 10.1002/cdt3.103 -
Foods (Basel, Switzerland) May 2024In this study, we investigated the anti-hypertensive properties of mulberry products by modulating the renin-angiotensin system (RAS). Comparative analysis showed that...
In this study, we investigated the anti-hypertensive properties of mulberry products by modulating the renin-angiotensin system (RAS). Comparative analysis showed that the ethyl acetate fractions, particularly from the Cheongil and Daeshim cultivars, contained the highest levels of polyphenols and flavonoids, with concentrations reaching 110 mg gallic acid equivalent (GE)/g and 471 mg catechin equivalent (CE)/g of extract, respectively. The ethyl acetate fraction showed superior angiotensin-converting enzyme (ACE) inhibitory activity, mainly because of the presence of the prenylated flavonoids kuwanon G and H. UPLC/Q-TOF-MS analysis identified kuwanon G and H as the primary active components, which significantly contributed to the pharmacological efficacy of the extract. In vivo testing of mice fed a high-salt diet showed that the ethyl acetate fraction substantially reduced the heart weight and lowered the serum renin and angiotensinogen levels by 34% and 25%, respectively, highlighting its potential to modulate the RAS. These results suggested that the ethyl acetate fraction of mulberry root bark is a promising candidate for the development of natural ACE inhibitors. This finding has significant implications for the management of hypertension through RAS regulation and the promotion of cardiovascular health in the functional food industry.
PubMed: 38790847
DOI: 10.3390/foods13101547 -
Hypertension (Dallas, Tex. : 1979) May 2024Angiotensin-(1-12), measured by a self-developed, polyclonal antibody-based radioimmunoassay, has been suggested to act as an alternative precursor of angiotensin II. A...
BACKGROUND
Angiotensin-(1-12), measured by a self-developed, polyclonal antibody-based radioimmunoassay, has been suggested to act as an alternative precursor of angiotensin II. A more reliable detection method would be liquid chromatography-tandem mass spectrometry.
METHODS
We set up the quantification of human and murine angiotensin-(1-12) by liquid chromatography-tandem mass spectrometry and then used this method to measure angiotensin-(1-12) in human and mouse blood samples, as well as in mouse brain and kidney. We also verified ex vivo angiotensin-(1-12) generation and metabolism in human blood samples incubated at 37 °C.
RESULTS
Stabilization of blood in guanidine hydrochloride was chosen for sample collection since this allowed full recovery of spiked angiotensin-(1-12). Angiotensin-(1-12) was undetectable in human blood samples when incubating nonstabilized plasma at 37 °C, while angiotensin-(1-12) added to nonstabilized human plasma disappeared within 10 minutes. Stabilized human blood samples contained angiotensin II, while angiotensin-(1-12) was undetectable. Blood, hearts, and kidneys, but not brains, of wild-type mice and rats contained detectable levels of angiotensin II, while angiotensin-(1-12) was undetectable. In renin knockout mice, all angiotensins, including angiotensin-(1-12), were undetectable at all sites, despite a 50% rise in angiotensinogen. Angiotensin-(1-12) metabolism in human blood plasma was not affected by renin inhibition. Yet, blockade of angiotensin-converting enzyme and aminopeptidase A, but not of chymase, neutral endopeptidase, or prolyl oligopeptidase, prolonged the half-life of angiotensin-(1-12), and angiotensin-converting enzyme inhibition prevented the formation of angiotensin II.
CONCLUSIONS
We were unable to detect intact angiotensin-(1-12) in humans or mice, either in blood or tissue, suggesting that this metabolite is an unlikely source of endogenous angiotensins.
PubMed: 38716648
DOI: 10.1161/HYPERTENSIONAHA.124.22856 -
Diabetes, Metabolic Syndrome and... 2024Hypertension is a leading cause of cardiovascular-related morbidity and mortality worldwide, with a prevalence increasing at an alarming rate in both middle- and...
PURPOSE
Hypertension is a leading cause of cardiovascular-related morbidity and mortality worldwide, with a prevalence increasing at an alarming rate in both middle- and low-income countries. Various environmental and genetic factors have been attributed to play a significant role in the increasing prevalence of hypertension. Single nucleotide polymorphisms (SNPs) in the angiotensinogen () gene are reported to have a significant association with hypertension; however, there are limited studies done on South African populations. Therefore, this case-control study aimed to investigate the association between SNPs (rs2004776, rs3789678, rs5051 and rs7079) with hypertension in a study population of isiXhosa-speaking participants from the Eastern Cape Province in South Africa.
MATERIALS AND METHODS
The SNPs were genotyped in 250 hypertensive cases and 237 normotensive controls, using TaqMan genotyping assays.
RESULTS
For the SNP rs2004776, the frequency of CC genotype (18.4%) and C allele (44%) in hypertensive cases showed no significant differences (p = 0.52, χ2 = 1.32), when compared to the normotensive control group (CC: 19.8% and C allele: 43%). Similar results were obtained for the genotypic and allelic frequencies between hypertensive cases and normotensive controls for rs3789678 (p = 0.88, χ2=0.26) and rs5051 (p = 0.57, χ2=1.12), and rs7079 (p = 0.33, χ2=2.23). These findings demonstrate that there were no significant associations between the SNPs rs2004776, rs3789678, rs7079, rs5051 with hypertension in our study population.
CONCLUSION
These findings suggest that gene polymorphisms are not associated with the development of hypertension in the studied population. The present study represents the first genetic report to investigate the gene polymorphisms with hypertension in an isiXhosa-speaking South African population.
PubMed: 38706806
DOI: 10.2147/DMSO.S452272 -
International Journal of Infectious... Jul 2024To analyze the gene variants of the renin-angiotensin-aldosterone system and determine their association with the severity and outcome of COVID-19.
Gene variants rs5182, rs2074192, and rs4343 in the renin-angiotensin-aldosterone system are associated with symptom severity, higher odds of hospitalization, and death in COVID-19.
OBJECTIVES
To analyze the gene variants of the renin-angiotensin-aldosterone system and determine their association with the severity and outcome of COVID-19.
METHODS
A total of 104 patients were included in the study: 34 asymptomatic patients with COVID-19 as controls and 70 symptomatic patients as cases. The genetic variants ACE rs4343, ACE2 rs2074192, AGTR1 rs5182, and AGT rs4762 were identified using TaqMan genotyping tests.
RESULTS
Patients with the T/T genotype of AGTR1 rs5182 have a higher probability of developing symptomatic COVID-19 (odds ratio [OR] 12.25, 95% confidence interval [CI] 1.34-111.9, P ≤0.001) and a higher risk of hospitalization because of disease (OR 14.00, 95% CI 1.53-128.49, P = 0.012). The haplotype CTG (AGTR1 rs5182, ACE2 rs2074192, ACE rs4343) decreased the odds of death related to COVID-19 in the study population (OR 0.03, 95% CI 0.0-0.06, P = 0.026).
CONCLUSIONS
The T/T genotype of the AGTR1 rs5182 variant increased the probability of symptomatic COVID-19 and hospitalization, whereas the haplotype CTG (consisting of AGTR1 rs5182, ACE2 rs2074192, and ACE rs4343) decreased the odds of death related to COVID-19 by 97% in the hospitalized patients with COVID-19. These results support the participation of renin-angiotensin-aldosterone system gene variants as modifiers of the severity of symptoms associated with SARS-CoV-2 infection and the outcome of COVID-19.
Topics: Humans; COVID-19; Male; Female; Hospitalization; Middle Aged; Receptor, Angiotensin, Type 1; Renin-Angiotensin System; Angiotensin-Converting Enzyme 2; SARS-CoV-2; Severity of Illness Index; Peptidyl-Dipeptidase A; Adult; Polymorphism, Single Nucleotide; Aged; Angiotensinogen; Genotype; Genetic Predisposition to Disease; Haplotypes; Case-Control Studies
PubMed: 38697603
DOI: 10.1016/j.ijid.2024.107067 -
Counteracting Angiotensinogen Small-Interfering RNA-Mediated Antihypertensive Effects With REVERSIR.Hypertension (Dallas, Tex. : 1979) Jul 2024Small-interfering RNA (siRNA) targeting hepatic AGT (angiotensinogen) mRNA depletes AGT, lowering blood pressure for up to 6 months. However, certain situations may...
BACKGROUND
Small-interfering RNA (siRNA) targeting hepatic AGT (angiotensinogen) mRNA depletes AGT, lowering blood pressure for up to 6 months. However, certain situations may require a rapid angiotensin increase. The REVERSIR (RVR) - reverse siRNA silencing technology a potential approach to counteract siRNA effects.
METHODS
Spontaneously hypertensive rats received 10 mg/kg AGT siRNA, and 3 weeks later were given AGT-RVR (1, 10, or 20 mg/kg). One week after AGT-RVR dosing, a redose of AGT siRNA assessed its post-AGT-RVR effectiveness for 2 weeks. Additionally, the impact of AGT-RVR after an equihypotensive dose of valsartan (4 mg/kg per day) was examined.
RESULTS
Baseline mean arterial pressure (MAP) was 144±1 mm Hg. AGT siRNA reduced MAP by ≈16 mm Hg and AGT by >95%, while renin increased 25-fold. All AGT-RVR doses restored MAP to baseline within 4 to 7 days. Notably, 10 and 20 mg/kg restored AGT and renin to baseline, while 1 mg/kg allowed ≈50% AGT restoration, with renin remaining above baseline. A second AGT siRNA treatment, following 1 mg/kg AGT-RVR, reduced MAP to the same degree as the initial dose, while following 10 mg/kg AGT-RVR, it resulted in ≈50% of the first dose's MAP effect at 2 weeks. The valsartan-induced MAP reduction was unaffected by AGT-RVR.
CONCLUSIONS
In spontaneously hypertensive rats, angiotensinogen-RVR dose-dependently reversed AGT siRNA-induced AGT reduction, normalizing MAP. MAP normalization persisted even with 50% recovered AGT levels, likely due to upregulated renin maintaining adequate angiotensin generation. Post-AGT-RVR dosing, a second AGT siRNA dose lowered MAP again.
Topics: Animals; Angiotensinogen; RNA, Small Interfering; Rats, Inbred SHR; Rats; Hypertension; Antihypertensive Agents; Male; Blood Pressure; Disease Models, Animal; Valsartan; Renin-Angiotensin System
PubMed: 38690653
DOI: 10.1161/HYPERTENSIONAHA.124.22878 -
MethodsX Jun 2024At present, the numbers of cultured erythroid cells obtained from culture systems are not on a scale that can be used for therapeutics since the cultured erythroid cells...
At present, the numbers of cultured erythroid cells obtained from culture systems are not on a scale that can be used for therapeutics since the cultured erythroid cells have limited proliferation capacity. Stromal cells are believed to play important roles during erythropoiesis. Our previous study shows that factors secreted by stromal cells enhance the proliferation capacity of adult erythroid cells in the culture system. Among the identified factors, angiotensinogen is one of the most abundant proteins secreted by the stromal cells. This study aims to investigate the effect of angiotensin II, an angiotensinogen derivative, on the proliferation of erythroid cells. •The receptor for angiotensin II was first checked by PCR analysis. It was expressed in erythroblasts at all stages during differentiation.•To study the effect of angiotensin II, CD34 hematopoietic stem cells were cultured in a 3-stage erythroid culture system with and without angiotensin II. The addition of angiotensin II to the culture media, from day 0 to 8, significantly increases the numbers of cultured erythroid cells, whereas no difference in enucleation is observed.
PubMed: 38660027
DOI: 10.1016/j.mex.2024.102714 -
Cells Apr 2024Glioblastoma is a highly aggressive disease with poor survival outcomes. An emerging body of literature links the role of the renin-angiotensin system (RAS), well-known...
Glioblastoma is a highly aggressive disease with poor survival outcomes. An emerging body of literature links the role of the renin-angiotensin system (RAS), well-known for its function in the cardiovascular system, to the progression of cancers. We studied the expression of RAS-related genes (, , , , , and ) in The Cancer Genome Atlas (TCGA) glioblastoma cohort, their relationship to patient survival, and association with tumour microenvironment pathways. The expression of RAS genes was then examined in 12 patient-derived glioblastoma cell lines treated with chemoradiation. In cases of glioblastoma within the TCGA, , , , and had consistent expressions across samples, while and were lowly expressed. High expression of was independently associated with lower progression-free survival (PFS) ( = 0.01) and had a non-significant trend for overall survival (OS) after multivariate analysis ( = 0.095). The combined expression of RAS receptors (, , and ) was positively associated with gene pathways involved in hypoxia, microvasculature, stem cell plasticity, and the molecular characterisation of glioblastoma subtypes. In patient-derived glioblastoma cell lines, and were upregulated after chemoradiotherapy and correlated with an increase in expression. This data suggests the RAS is correlated with changes in the tumour microenvironment and associated with glioblastoma survival outcomes.
Topics: Humans; Renin-Angiotensin System; Up-Regulation; Glioblastoma; Tumor Microenvironment; Receptors, Cell Surface; Prorenin Receptor
PubMed: 38607073
DOI: 10.3390/cells13070634 -
Journal of Pharmacy & Bioallied Sciences Feb 2024Alteration in the various markers is seen in diabetic nephropathy (DN). In the current research, four different markers were evaluated and were examined for their...
INTRODUCTION
Alteration in the various markers is seen in diabetic nephropathy (DN). In the current research, four different markers were evaluated and were examined for their diagnostic value in the nephropathic type 2 diabetes patients.
METHODS
A prospective clinical trial was piloted with diabetic male subjects with nephropathy. The subjects were followed up for 9 months. Thirty subjects were recruited as type 2 diabetes mellitus patients without nephropathy as controls. The interventional groups were grouped again as microalbuminuria, normoalbuminuria, and hyperfiltration. All of them underwent testing for urinary biomarkers like urine protein, ACR, HbA1C, and estimated glomerular filtration rate (eGFR). Correlation and logistic regression were used to compare all diagnostic tests across various groupings.
RESULTS
The greatest area under curve (AUC) values were .90 and .91 for AGT and AGT/Cr, respectively. The AUC, specificity, sensitivity, and cut-off value of AGT/Cr were, respectively, .91, 85%, 91%, and 4.36 mg/g. When using urine as the cut-off, the sensitivity was 42 and 100 for ACR and eGFR both. All other biomarkers had lower values than the AGT. Less than. 50 was evident for NGAL/Cr and NAGL.
CONCLUSIONS
To identify DN, before the initiation of the albuminuria, compared to other diagnostic markers, urinary AGT demonstrated a greater diagnostic value. Further research is suggested to corroborate the findings.
PubMed: 38595634
DOI: 10.4103/jpbs.jpbs_494_23 -
Arteriosclerosis, Thrombosis, and... May 2024AGT (angiotensinogen) is the unique precursor for the generation of all the peptides of the renin-angiotensin system, but it has received relatively scant attention... (Review)
Review
AGT (angiotensinogen) is the unique precursor for the generation of all the peptides of the renin-angiotensin system, but it has received relatively scant attention compared to many other renin-angiotensin system components. Focus on AGT has increased recently, particularly with the evolution of drugs to target the synthesis of the protein. AGT is a noninhibitory serpin that has several conserved domains in addition to the angiotensin II sequences at the N terminus. Increased study is needed on the structure-function relationship to resolve many unknowns regarding AGT metabolism. Constitutive whole-body genetic deletion of in mice leads to multiple developmental defects creating a challenge to use these mice for mechanistic studies. This has been overcome by creating -floxed mice to enable the development of cell-specific deficiencies that have provided considerable insight into a range of cardiovascular and associated diseases. This has been augmented by the recent development of pharmacological approaches targeting hepatocytes in humans to promote protracted inhibition of AGT synthesis. Genetic deletion or pharmacological inhibition of has been demonstrated to be beneficial in a spectrum of diseases experimentally, including hypertension, atherosclerosis, aortic and superior mesenteric artery aneurysms, myocardial dysfunction, and hepatic steatosis. This review summarizes the findings of recent studies utilizing AGT manipulation as a therapeutic approach.
Topics: Animals; Humans; Cardiovascular Diseases; Angiotensinogen; Metabolic Diseases; Renin-Angiotensin System; Molecular Targeted Therapy
PubMed: 38572647
DOI: 10.1161/ATVBAHA.124.318374