A loss-of-function AGTR1 variant in a critically-ill infant with renal tubular dysgenesis: case presentation and literature review

BACKGROUND

Renal tubular dysgenesis (RTD) is a severe disorder with poor prognosis significantly impacting the proximal tubules of the kidney while maintaining an anatomically normal gross structure. The genetic origin of RTD, involving variants in the ACE, REN, AGT, and AGTR1 genes, affects various enzymes or receptors within the Renin angiotensin system (RAS). This condition manifests prenatally with oligohydramninos and postnatally with persistent anuria, severe refractory hypotension, and defects in skull ossification.

CASE PRESENTATION

In this report, we describe a case of a female patient who, despite receiving multi vasopressor treatment, experienced persistent hypotension, ultimately resulting in early death at five days of age. While there was a history of parental consanguinity, no reported family history of renal disease existed. Blood samples from the parents and the remaining DNA sample of the patient underwent Whole Genome Sequencing (WGS). The genetic analysis revealed a rare homozygous loss of function variant (NM_000685.5; c.415C > T; p.Arg139*) in the Angiotensin II Receptor Type 1 (AGTR1) gene.

CONCLUSION

This case highlights the consequence of loss-of-function variants in AGTR1 gene leading to RTD, which is characterized by high mortality rate at birth or during the neonatal period. Furthermore, we provide a comprehensive review of previously reported variants in the AGTR1 gene, which is the least encountered genetic cause of RTD, along with their associated clinical features.

Identification of membrane palmitoylated protein 1 (MPP1) as a heart-failure-promoting protein triggered by cardiovascular risk factors and aging

Membrane-Associated Guanylate Kinase (MAGUK) proteins are scaffold proteins with well-established functions in the neuronal system. A role of MAGUK protein up-regulation in the pathogenesis of heart failure is not established. This study identified the up-regulation of the MAGUK family protein MPP1 (Membrane Palmitoylated Protein 1), in cardiac transcriptome data of three different heart failure models. MPP1 was up-regulated in failing hearts of B6 mice with long-term chronic pressure overload, in failing hearts of aged Apoe-/- mice with long-term atherosclerosis, and in failing hearts of RKIP-transgenic mice with cardiotoxic lipid overload. MPP1-transgenic mice revealed that moderately (2-fold) increased cardiac MPP1 levels caused symptoms of heart failure with a significantly reduced left ventricular ejection fraction of 39.0 ± 6.9 % in Tg-MPP1 mice compared to 55.2 ± 3.7 % of non-transgenic B6 controls. Echocardiographic and histological analyses detected cardiac enlargement and cardiac dilation in Tg-MPP1 mice. The angiotensin II AT1 receptor (AGTR1) and MPP1 were co-localized on sarcolemmal membranes in vivo, and Tg-MPP1 mice had increased levels of cardiac AGTR1, which has an established heart failure-promoting function. The increased AGTR1 protein could be directly triggered by elevated MPP1 because MPP1 also increased the AGTR1 protein in non-cardiomyocyte HEK cells, which was detected by fluorescence measurement of AGTR1eYFP. MPP1 was not only up-regulated by major cardiovascular risk factors but also by old age, which is a major contributor to heart failure. Thus, the aging-induced MPP1 exerts a previously unrecognized role in heart failure pathogenesis by upregulation of the angiotensin II AT1 receptor (AGTR1) protein.

Association between AGTR1 (c.1166 A>C) Polymorphisms and Kidney Injury in Hypertension

BACKGROUND

High blood pressure is the main cause of cardiovascular diseases. Kidney damage is one of the most common organ secondary damage to hypertension. The study of hypertension gene polymorphisms is an important means of precision treatment of primary hypertension.

OBJECTIVES

The objective of this study was to explore the relationship between AGTR1 (c.1166 A>C) gene polymorphisms and hypertension combined with kidney damage, while exploring the relationship between codominant, dominant and recessive gene model and hypertension with kidney injury and the susceptibility of different genotypes to hypertension with kidney injury.

METHODS

The distribution of AGTR1 polymorphism in the AGTR1 in hypertensive patients (hypertension group, 292 patients) and hypertension with kidney injury patients (44 patients) were detected and compared by PCR-melting curve method.

RESULTS

The genotype distribution of hypertension and combined groups met Hardy-Weinberg equilibrium (p > 0.05); the distribution difference between the three genotypes was statistically significant (p < 0.05), the codominant, dominant and recessive distribution frequency of genotypes (p < 0.05), and no difference between A allele and C allele (p > 0.05).

CONCLUSIONS

Our study identified the relationship of AGTRA (c.1166 A>C) with hypertension combined with renal injury, and compared the susceptibility of different genetic models, which may provide novel targets for precision gene therapy of hypertension.

CLINICAL TRIAL REGISTRATION

URL: https://www.chictr.org.cn/indexEN.html; Unique identifier: ChiCTR2100051472.

Molecular docking analysis of AGTR1 antagonists

Cardiovascular diseases (CVDs) are the leading cause of death and morbidity globally. The renin-angiotensin system is an important regulatory system for maintaining cardiovascular and renal function. Therefore, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have emerged as first-line treatments for conditions such as hypertension and heart failure. Currently available synthetic medications used to treat various CVDs have been linked with various adverse effects. Therefore, this study focuses on targeting type-1 angiotensin II receptor (AGTR1) by natural compounds. The ZINC database natural compounds and standard AGTR1 inhibitors have been screened against the AGTR1 active site. The results showed that five compounds, namely ZINC85625504, ZINC62001623, ZINC70666587, ZINC06624086, and ZINC95486187, had similar binding energies to established AGTR1 inhibitors. These compounds were found to interact with crucial AGTR1 residues, indicating their potential as AGTR1 inhibitors. Moreover, the hit compounds demonstrated favorable drug-like characteristics and warrant further investigation for their potential use in managing CVD.

Angiotensin receptor blockers retard the progression and fibrosis via inhibiting the viability of AGTR1+ CAFs in intrahepatic cholangiocarcinoma

BACKGROUND

Intrahepatic cholangiocarcinoma (iCCA) is a highly lethal malignancy characterized by massive fibrosis and has ineffective adjuvant therapies. Here, we demonstrate the potential of angiotensin receptor blockers (ARBs) in targeting iCCA.

METHODS

Masson's trichrome staining was used to assess the effect of ARBs in iCCA specimens, CCK8 and gel contraction assays in vitro and in xenograft models in vivo. RNA-seq and ATAC-seq were used for mechanistic investigations.

RESULTS

Patients with iCCA who were administered ARBs had a better prognosis and a lower proportion of tumour stroma, indicating alleviated fibrosis. The presence of AGTR1, the ARBs receptor, is associated with a poor prognosis of iCCA and is highly expressed in tumour tissues and cancer-associated fibroblasts (CAFs). The ARBs strongly attenuated the viability of AGTR1+ CAFs in vitro and retarded tumour progression and fibrosis in xenograft models of co-cultured CAFs and iCCA cells. Still, they did not have a significant effect on AGTR1- CAFs. Moreover, ARBs decreased the secretion of AGTR1+ CAF-derived MFAP5 via the Hippo pathway, weakened the interaction between CAFs and iCCA cells, and impaired the aggressiveness of iCCA cells by attenuating the activation of the Notch1 pathway in iCCA cells.

CONCLUSIONS

ARBs exhibit anti-fibrotic function by inhibiting the viability of AGTR1+ CAFs. These findings support using ARBs as a novel therapeutic option for targeting iCCA.

Association between AT1 receptor gene polymorphism and left ventricular hypertrophy and arterial stiffness in essential hypertension patients: a prospective cohort study

BACKGROUND

AT1 receptor gene (AGTR1) is related to essential hypertension (EH), and left ventricular hypertrophy (LVH) and arterial stiffness are common complications of EH. This study aimed to explore the association between AGTR1 genotype and LVH and arterial stiffness in EH patients.

METHODS

A total of 179 EH patients were recruited in this study. Oral exfoliated cells were collected from each patient, and the genetic polymorphism of AGTR1(rs4524238) was assessed using a gene sequencing platform. The outcomes were LVH and arterial stiffness.

RESULTS

Among 179 patients, 114 were with AGTR1 genotype of GG (57 males, aged 59.54 ± 13.49 years) and 65 were with AGTR1 genotype of GA or AA (36 males, aged 61.28 ± 12.79 years). Patients with AGTR1 genotype of GG were more likely to have LVH (47 [41.23%] vs. 14 [21.54%], P = 0.006) and arterial stiffness (30 [26.32%] vs. 8 [12.31%], P = 0.036). The AGTR1 polymorphism frequency was in accordance with Hardy-Weinberg equilibrium (P = 0.291). The multivariate logistic regression showed that AGTR1 genotype of GA or AA was independently associated with lower risk of LVH (OR = 0.344, 95%CI 160~0.696, P = 0.003) and arterial stiffness (OR = 0.371, 95%CI 0.155~0.885, P = 0.025) after adjusting for gender, age, and diabetes.

CONCLUSION

EH patients with the AGTR1 genotype of GA or AA were at lower risk for LVH and arterial stiffness than those with the GG genotype.

Targeted Delivery of Antisense Oligonucleotides Through Angiotensin Type 1 Receptor

We evaluated the potential of AGTR1, the principal receptor for angiotensin II (Ang II) and a member of the G protein-coupled receptor family, for targeted delivery of antisense oligonucleotides (ASOs) in cells and tissues with abundant AGTR1 expression. Ang II peptide ASO conjugates maintained robust AGTR1 signaling and receptor internalization when ASO was placed at the N-terminus of the peptide, but not at C-terminus. Conjugation of Ang II peptide improved ASO potency up to 12- to 17-fold in AGTR1-expressing cells. Additionally, evaluation of Ang II conjugates in cells lacking AGTR1 revealed no enhancement of ASO potency. Ang II peptide conjugation improves potency of ASO in mouse heart, adrenal, and adipose tissues. The data presented in this report add to a growing list of approaches for improving ASO potency in extrahepatic tissues.

AGTR1 Inhibits the Progression of Lung Adenocarcinoma

Purpose

The occurrence and development of lung adenocarcinoma (LUAD) are related to many factors. Multiple researches showed that the renin-angiotensin system (RAS) plays an important role in lung cancer. This research mainly focuses on angiotensin II receptor 1 (AT1R) encoding gene AGTR1, an important part of the RAS.

Methods

We comprehensively evaluated the expression of AGTR1 in pan-cancer based on RNA sequencing data obtained from The Cancer Genome Atlas (TCGA). We explored the correlation of AGTR1 with clinicopathological features, prognosis and tumor microenvironment in LUAD. We also explored the mechanism through enrichment analysis and verified it with cell lines and tissue samples.

Results

We found that AGTR1 was less expressed in most tumors and related to prognosis based on the TCGA database. To further explore its mechanism, we mainly focused on LUAD. Combined with the verification results in the GEO database, AGTR1 was associated with a better prognosis in LUAD. High expression of AGTR1 was associated with less lymph node metastasis (P=0.007) and MET mutation (P=0.019). High expression of AGTR1 was related to the anti-tumor immune microenvironment with high infiltration of B cells, myeloid dendritic cells, monocytes, and low infiltration of myeloid-derived suppressor cells (all P<0.05). Enrichment analysis and in vitro verification results showed that AGTR1 was likely to play a role in LUAD through the PI3K/AKT3 pathway. Finally, we verified the above results through tissue samples and the construction of AGTR1 overexpressing cells.

Conclusion

AGTR1 inhibits the progression of lung adenocarcinoma through the PI3K/AKT3 pathway.

Association between angiotensinogen (AGT), angiotensin-converting enzyme (ACE) and angiotensin-II receptor 1 (AGTR1) polymorphisms and COVID-19 infection in the southeast of Iran: a preliminary case-control study

BACKGROUND

The COVID-19 pandemic remains an emerging public health crisis with serious adverse effects. The disease is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV--2) infection, targeting angiotensin-converting enzyme-2 (ACE2) receptor for cell entry. However, changes in the renin-angiotensin system (RAS) balance alter an individual's susceptibility to COVID-19 infection. We aimed to evaluate the association between AGT rs699 C > T, ACE rs4646994 I/D, and AGTR1 rs5186 C > A variants and the risk of COVID-19 infection and the severity in a sample of the southeast Iranian population.

METHODS

A total of 504 subjects, including 258 COVID-19 positives, and 246 healthy controls, were recruited. Genotyping of the ACE gene rs4646994, and AGT rs699, and AGTR1 rs5186 polymorphisms was performed by polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP), respectively.

RESULTS

Our results showed that the II genotype of ACE rs4646994 and the I allele decreased the risk of COVID-19 infection. Moreover, we found that the TC genotype and C allele of AGT rs699 increased the risk of COVID-19 infection. The AGTR1 rs5186 was not associated with COVID-19 infection. Also, we did not find any association between these polymorphisms and the severity of the disease. However, we found a significantly higher age and prevalence of diabetes and hypertension in patients with severe disease than a non-severe disease.

CONCLUSIONS

These findings suggest that ACE rs4646994 and AGT rs699 polymorphisms increase the risk of COVID-19 infection in a southeast Iranian population.

Stearoyl-CoA Desaturase (SCD) Induces Cardiac Dysfunction with Cardiac Lipid Overload and Angiotensin II AT1 Receptor Protein Up-Regulation

Heart failure is a major cause of death worldwide with insufficient treatment options. In the search for pathomechanisms, we found up-regulation of an enzyme, stearoyl-CoA desaturase 1 (Scd1), in different experimental models of heart failure induced by advanced atherosclerosis, chronic pressure overload, and/or volume overload. Because the pathophysiological role of Scd1/SCD in heart failure is not clear, we investigated the impact of cardiac SCD upregulation through the generation of C57BL/6-Tg(MHCSCD)Sjaa mice with myocardium-specific expression of SCD. Echocardiographic examination showed that 4.9-fold-increased SCD levels triggered cardiac hypertrophy and symptoms of heart failure at an age of eight months. Tg-SCD mice had a significantly reduced left ventricular cardiac ejection fraction of 25.7 ± 2.9% compared to 54.3 ± 4.5% of non-transgenic B6 control mice. Whole-genome gene expression profiling identified up-regulated heart-failure-related genes such as resistin, adiponectin, and fatty acid synthase, and type 1 and 3 collagens. Tg-SCD mice were characterized by cardiac lipid accumulation with 1.6- and 1.7-fold-increased cardiac contents of saturated lipids, palmitate, and stearate, respectively. In contrast, unsaturated lipids were not changed. Together with saturated lipids, apoptosis-enhancing p53 protein contents were elevated. Imaging by autoradiography revealed that the heart-failure-promoting and membrane-spanning angiotensin II AT1 receptor protein of Tg-SCD hearts was significantly up-regulated. In transfected HEK cells, the expression of SCD increased the number of cell-surface angiotensin II AT1 receptor binding sites. In addition, increased AT1 receptor protein levels were detected by fluorescence spectroscopy of fluorescent protein-labeled AT1 receptor-Cerulean. Taken together, we found that SCD promotes cardiac dysfunction with overload of cardiotoxic saturated lipids and up-regulation of the heart-failure-promoting AT1 receptor protein.

LINC00852 promotes the proliferation and invasion of ovarian cancer cells by competitively binding with miR-140-3p to regulate AGTR1 expression

Background

Dysregulation of long non-coding RNAs (lncRNAs) has been identified in ovarian cancer. However, the expression and biological functions of LINC00852 in ovarian cancer are not understood.

Methods

The expressions of LINC00852, miR-140-3p and AGTR1 mRNA in ovarian cancer tissues and cells were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. Gain- and loss-of-function assays were performed to explore the biological functions of LINC00852 and miR-140-3p in the progression of ovarian cancer in vitro. The bindings between LINC00852 and miR-140-3p were confirmed by luciferase reporter gene assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay.

Results

We found that LINC00852 expression was significantly up-regulated in ovarian cancer tissues and cells, whereas miR-140-3p expression was significantly down-regulated in ovarian cancer tissues. Functionally, LINC00852 knockdown inhibited the viability, proliferation and invasion of ovarian cancer cells, and promoted the apoptosis of ovarian cancer cells. Further investigation showed that LINC00852 interacted with miR-140-3p, and miR-140-3p overexpression suppressed the viability, proliferation and invasion of ovarian cancer cells. In addition, miR-140-3p interacted with AGTR1 and negatively regulated its level in ovarian cancer cells. Mechanistically, we found that LINC00852 acted as a ceRNA of miR-140-3p to promote AGTR1 expression and activate MEK/ERK/STAT3 pathway. Finally, LINC00852 knockdown inhibited the growth and invasion ovarian cancer in vivo.

Conclusion

LINC00852/miR-140-3p/AGTR1 is an important pathway to promote the proliferation and invasion of ovarian cancer.

Angiotensin II receptor type 1 - An update on structure, expression and pathology

The AT₁ receptor, a major effector of the renin-angiotensin system, has been extensively studied in the context of cardiovascular and renal disease. Moreover, angiotensin receptor blockers, sartans, are among the most frequently prescribed drugs for the treatment of hypertension, chronic heart failure and chronic kidney disease. However, precise molecular insights into the structure of this important drug target have not been available until recently. In this context, seminal studies have now revealed exciting new insights into the structure and biased signaling of the receptor and may thus foster the development of novel therapeutic approaches to enhance the efficacy of pharmacological angiotensin receptor antagonism or to enable therapeutic induction of biased receptor activity. In this review, we will therefore highlight these and other seminal publications to summarize the current understanding of the tertiary structure, ligand binding properties and downstream signal transduction of the AT₁ receptor.

Angiotensin System Polymorphisms' in SARS-CoV-2 Positive Patients: Assessment Between Symptomatic and Asymptomatic Patients: A Pilot Study

Introduction

The renin-angiotensin-aldosterone system (RAAS), a metabolic cascade regulating pressure and circulating blood volume, has been considered the main system involved in the pathogenesis of severe lung injury and organs decline in COVID-19 patients. The angiotensin I-converting enzyme (ACE1), angiotensin-converting enzyme 2 (ACE2), angiotensinogen (AGT) and receptors angiotensin II receptor type 1 (AGTR1) are key factors for SARS-CoV-2 entering in the cells, sodium and water retention with an increase blood pressure, promotion of fibrotic and inflammatory phenomena resulting in a cytokine storm.

Methods

In this pilot study, the frequencies of six polymorphisms in the ACE1, ACE2, AGT and AGTR1 genes were analysed in symptomatic patients affected by COVID-19 and compared with the results obtained from asymptomatic subjects.

Results

Thus, we have identified that rs2074192 (ACE2), rs1799752 (ACE1) and rs699 (AGT) SNPs could potentially be a valuable tool for predicting the clinical outcome of SARS-CoV-2 infected patients. A genetic predisposition may be prospected for severe internal organ damages and poor prognosis in patients with COVID-19 disease, as observed in symptomatic vs asymptomatic.

Conclusion

This study provides evidence that analysis of RAAS polymorphisms could be considered the key point in understanding and predicting the SARS-CoV-2 course infection.

Immune Profiling of Parkinson's Disease Revealed Its Association With a Subset of Infiltrating Cells and Signature Genes

Parkinson’s disease (PD) is an age-related and second most common neurodegenerative disorder. In recent years, increasing evidence revealed that peripheral immune cells might be able to infiltrate into brain tissues, which could arouse neuroinflammation and aggravate neurodegeneration. This study aimed to illuminate the landscape of peripheral immune cells and signature genes associated with immune infiltration in PD. Several transcriptomic datasets of substantia nigra (SN) from the Gene Expression Omnibus (GEO) database were separately collected as training cohort, testing cohort, and external validation cohort. The immunoscore of each sample calculated by single-sample gene set enrichment analysis was used to reflect the peripheral immune cell infiltration and to identify the differential immune cell types between PD and healthy participants. According to receiver operating characteristic (ROC) curve analysis, the immunoscore achieved an overall accuracy of the area under the curve (AUC) = 0.883 in the testing cohort, respectively. The immunoscore displayed good performance in the external validation cohort with an AUC of 0.745. The correlation analysis and logistic regression analysis were used to analyze the correlation between immune cells and PD, and mast cell was identified most associated with the occurrence of PD. Additionally, increased mast cells were also observed in our in vivo PD model. Weighted gene co-expression network analysis (WGCNA) was used to selected module genes related to a mast cell. The least absolute shrinkage and selection operator (LASSO) analysis and random-forest analysis were used to analyze module genes, and two hub genes RBM3 and AGTR1 were identified as associated with mast cells in the training cohort. The expression levels of RBM3 and AGTR1 in these cohorts and PD models revealed that these hub genes were significantly downregulated in PD. Moreover, the expression trend of the aforementioned two genes differed in mast cells and dopaminergic (DA) neurons. In conclusion, this study not only exhibited a landscape of immune infiltrating patterns in PD but also identified mast cells and two hub genes associated with the occurrence of PD, which provided potential therapeutic targets for PD patients (PDs).

Distributive characteristics of the CYP2C9 and AGTR1 genetic polymorphisms in Han Chinese hypertensive patients: a retrospective study

Background

There is an individual variation in response to antihypertensive effect of the angiotensin II receptor antagonist. This study aimed to determine the allele and genotype frequencies of CYP2C9 and AGTR1 genetic polymorphisms and explore the potential role of these polymorphisms in guiding the selection of angiotensinIIreceptor antagonist in Han Chinese hypertensive patients.

Methods

Totally 2419 Han Chinese hypertensive patients and 126 normotensive controls were recruited in this study. Venous blood samples were collected from each patient, and the genetic polymorphisms of CYP2C9 and AGTR1 were assessed using a gene chip platform. The allele and genotype frequency of each gene and the combined genotypes in this study were analyzed respectively.

Results

The gene chip analysis identified an allelic frequency of 96.51% for CYP2C9*1 and 3.49% for CYP2C9*3 in the cohort of Han Chinese hypertensive patients. Statistical analysis showed that the frequency of wild-type homozygous for CYP2C9*1/*1 was 93.30%, while the frequency of heterozygous for *1/*3 or mutant homozygous for *3/*3 was 6.41% or 0.29%. Meanwhile, we detected allelic frequencies of 95.06% and 4.94% for the A and C allele of AGTR1, respectively. While the genotype frequency of wild-type homozygous for AA was 90.41%, the frequency of heterozygous for AC or mutant homozygous for CC was 9.30% or 0.29%. Notably, we observed that 84.66% (2048/2419) of the subjects exhibited a combined genotype of CYP2C9 and AGTR1 as *1/*1 + AA, while the combined genotypes *3/*3 + AC or *3/*3 + CC were not detected in hypertension patients. Besides, no significant association was found between normotensive controls and hypertensive patients, or among the three grades of hypertensive patients.

Conclusions

These data revealed the polymorphisms characteristics of CYP2C9 and AGTR1 in Han Chinese hypertensive patients, providing valuable information for genotype-based antihypertension therapy in prospective clinical studies in the future.

Clinical applicability of renin-angiotensin system inhibitors in cancer treatment

The renin-angiotensin system (RAS) regulates physiological functions of the cardiovascular system, kidneys, and other tissues. Various in vivo and in vitro studies have shown that RAS plays a pivotal role in the development of malignant tumors, while several retrospective studies have confirmed that patients undergoing long-term RAS inhibitors (RASi) treatment have a lowered risk of cancer. Moreover, blocking RAS has been shown to inhibit tumor growth, metastasis, and angiogenesis in various experimental models of malignant tumors. Herein, we review the available RASi-related literature and provide an analysis using the scientific atlas software VOSviewer. We observed that recent studies have primarily focused on gene expression, tumor biology, and survival analysis. Through an in-depth data analysis from the Cancer Genome Atlas (TCGA) and Genotype Tissue Expression (GTEx), we identified the impact of AGTR1, an essential component of RAS, on tumors, and we discuss the underlying biological mechanism of RASi. Furthermore, we outline the research progress and potential use of RASi in tumor treatment. Overall, RASi may be a promising adjunct in cancer therapy.

Functional tests to guide management in an adult with loss of function of type-1 angiotensin II receptor

BACKGROUND

Genetic loss of function of AGT (angiotensinogen), REN (renin), ACE (angiotensin-converting enzyme), or AGTR1 (type-1 angiotensin II receptor) leads to renal tubular dysgenesis (RTD). This syndrome is almost invariably lethal. Most surviving patients reach stage 5 chronic kidney disease at a young age.

METHODS

Here, we report a 28-year-old male with a homozygous truncating mutation in AGTR1 (p.Arg216*), who survived the perinatal period with a mildly impaired kidney function. In contrast to classic RTD, kidney biopsy showed proximal tubules that were mostly normal. During the subsequent three decades, we observed evidence of both tubular dysfunction (hyperkalemia, metabolic acidosis, salt-wasting and a urinary concentrating defect) and glomerular dysfunction (reduced glomerular filtration rate, currently ~30 mL/min/1.73 m², accompanied by proteinuria). To investigate the recurrent and severe hyperkalemia, we performed a patient-tailored functional test and showed that high doses of fludrocortisone induced renal potassium excretion by 155%. Furthermore, fludrocortisone lowered renal sodium excretion by 39%, which would have a mitigating effect on salt-wasting. In addition, urinary pH decreased in response to fludrocortisone. Opposite effects on urinary potassium and pH occurred with administration of amiloride, further supporting the notion that a collecting duct is present and able to react to fludrocortisone.

CONCLUSIONS

This report provides living proof that even truncating loss-of-function mutations in AGTR1 are compatible with life and relatively good GFR and provides evidence for the prescription of fludrocortisone to treat hyperkalemia and salt-wasting in such patients.

[Study on mechanism of Tibetan medicine Zuomua Decoction in treatment of hypertension based on network pharmacology and molecular docking technology]

Hypertension is a kind of chronic cardiovascular system disease caused by a series of factors and carriers dysfunction, which belongs to the category of Tibetan medicine &quot;Chalong disease&quot;, and has a high rate of disability and mortality. Zuomua Decoction is a classical Tibetan medicine for Chalong disease, but its mechanism is not clear. Therefore, in this paper we explored the multi-components, multi-targets and multi-channels mechanism of Zuomua Decoction in the treatment of hypertension based on network pharmacology and molecular docking technology. First of all, the chemical components of Zuomua Decoction were obtained in the retrieval of traditional Chinese medicine systems pharmacology database(TCMSP), China National Knowledge Infrastructure(CNKI) and Wanfang database. The potential targets of Zuomua Decoction were predicted by BATMAN-TCM database, and the targets of hypertension were obtained by using DisGeNET database. The intersection of these two targets set was taken to obtain the potential targets of Zuomua Decoction in the treatment of hypertension, and then the chemical compositions-targets network was constructed. Secondly, the intersection targets were imported into STRING database to obtain the interaction relationship of intersection targets, and the protein interaction network of Zuomua Decoction in the treatment of hypertension was constructed in Cytoscape. Topological, GO, and KEGG enrichment analysis were used to construct the key targets-signal pathways-biological processes network diagram and explore the mechanism of Zuomua Decoction in the treatment of hypertension. Finally, the key targets were selected to construct the pharmacodynamic identification models to verify the effect mode of Zomua Decoction in treating hypertension. The results showed that there were 61 chemical components and 90 potential targets in the compounds-targets network. We obtained 21 key targets, 154 signal pathways, and 382 biological processes in topological, GO, and KEGG enrichment analysis of the protein interaction network, and in the comprehensive analysis, it was found that Zuomua Decoction could reduce blood pressure by regulating renin angiotension aldosterone system, balancing the concentration of intracellular calcium and sodium ions and regulating vasoconstriction and relaxation. ACE, AGTR1, and ADRB2 were used as the carriers for molecular docking study on the components of Zuoma Decoction, and the results showed that the chemical components of Zuomua Decoction had a good binding activity with key targets. The purpose of this study is to provide ideas for the in-depth study of Zuoma Decoction in the treatment of hypertension, and provide scientific basis for its clinical rational application.

AGTR1 Is Overexpressed in Neuroendocrine Neoplasms, Regulates Secretion and May Potentially Serve as a Target for Molecular Imaging and Therapy

Simple Summary

Clinical management of neuroendocrine neoplasms (NEN), especially of those low in target molecules such as somatostatin receptors, may benefit from the discovery of novel targets. This study identified and confirmed angiotensin II (ATII) as a strong activator of signaling in NEN cells and its cognate receptor AGTR1 as overexpressed in human small intestinal NEN. NEN cells with high AGTR1 expression exhibited cellular activation and secretion upon stimulation with ATII. AGTR1 ligand saralasin coupled to a fluorescent dye demonstrated tumor accumulation in an animal model of NEN. This proof of concept establishes AGTR1 as a novel target in NEN, paving the way for its potential use in diagnostic PET imaging and radioligand therapy.

Abstract

This study identified and confirmed angiotensin II (ATII) as a strong activator of signaling in neuroendocrine neoplasm (NEN) cells. Expression analyses of the ATII receptor type 1 (AGTR1) revealed an upregulation of mRNA levels (RT-qPCR) and radioligand binding (autoradiography) in small-intestinal (n = 71) NEN tissues compared to controls (n = 25). NEN cells with high AGTR1 expression exhibited concentration-dependent calcium mobilization and chromogranin A secretion upon stimulation with ATII, blocked by AGTR1 antagonism and Gαq inhibition. ATII also stimulated serotonin secretion from BON cells. AGTR1 ligand saralasin was coupled to a near-infrared fluorescent (NIRF) dye and tested for its biodistribution in a nude mouse model bearing AGTR1-positive BON and negative QGP-1 xenograft tumors. NIRF imaging showed significantly higher uptake in BON tumors. This proof of concept establishes AGTR1 as a novel target in NEN, paving the way for translational chelator-based probes for diagnostic PET imaging and radioligand therapy.

Targeting AGTR1/NF-κB/CXCR4 axis by miR-155 attenuates oncogenesis in glioblastoma

Glioblastoma (GBM) represents the most aggressive malignancy of the central nervous system. Increased expression of Angiotensin II Receptor Type 1 (AGTR1) has been associated with proliferative and infiltrative properties of glioma cells. However, the underlying mechanism of AGTR1 upregulation in GBM is still unexplored. To understand the post-transcriptional regulation of AGTR1 in GBM, we screened 3'untranslated region (3'UTR) of AGTR1 for putative miRNA binding by using prediction algorithms. Interestingly, miR-155 showed conserved binding on the 3'UTR of AGTR1, subsequently confirmed by luciferase reporter assay. Furthermore, miR-155 overexpressing GBM cells show decrease in AGTR1 expression accompanied with reduced cell proliferation, invasion, foci formation and anchorage-independent growth. Strikingly, immunodeficient mice implanted with stable miR-155 overexpressing SNB19 cells show negligible tumor growth. Notably, miR-155 attenuates NF-κB signaling downstream of AGTR1 leading to reduced CXCR4 as well as AGTR1 levels. Mechanistically, miR-155 mitigates AGTR1-mediated angiogenesis, epithelial-to-mesenchymal transition, stemness, and MAPK signaling. Similar effects were observed by using pharmacological inhibitor of IκB Kinase (IKK) complex in multiple cell-based assays. Taken together, we established that miRNA-155 post-transcriptionally regulates AGTR1 expression, abrogates AGTR1/NF-κB/CXCR4 signaling axis and elicits pleiotropic anticancer effects in GBM. This study opens new avenues for using IKK inhibitors and miRNA-155 replacement therapies for the treatment of AGTR1-positive malignancies.

DNA methylation of hypertension-related genes and effect of riboflavin supplementation in adults stratified by genotype for the MTHFR C677T polymorphism

BACKGROUND

The interaction between genetic, epigenetic and environmental factors plays an important role in the aetiology of hypertension. GWAS and observational studies link the C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR) with hypertension, while riboflavin, the MTHFR cofactor, has been shown to reduce blood pressure and global DNA methylation in homozygous (TT genotype) individuals. It is currently unclear whether riboflavin modulates DNA methylation of other hypertension-related genes.

OBJECTIVES

To compare DNA methylation of hypertension-related genes in adults stratified by MTHFR genotype and effect of riboflavin intervention in adults with the variant MTHFR 677TT genotype.

METHOD

Pyrosequencing was carried out for hypertension-related genes (ACE, AGTR1, GCK, GNA12, IGF2, MMP9 and NOS3) in blood samples from participants in previous trials (CC, n = 40; TT, n = 40). The effect of intervention with riboflavin (1.6 mg/d for16 weeks) or placebo on DNA methylation was investigated in adults with the variant MTHFR 677TT genotype (n = 80).

RESULTS

Individuals with the MTHFR 677TT v CC genotype had significantly higher average DNA methylation at NOS3 (+1.66%, P = 0.044). In response to riboflavin supplementation in TT individuals, there was an increase in average DNA methylation at IGF2 (+1.09%, P = 0.019) and a decrease at ACE (-0.44%, P = 0.021) in females only. Specific CpG sites were hypomethylated in GNA12 and hypermethylated in AGTR1.

CONCLUSION

This study provides the first RCT evidence that riboflavin alters DNA methylation of hypertension-related genes in adults with the MTHFR 677TT genotype, providing some insight into mechanisms linking hypertension with the genotype-specific response of BP to riboflavin.

AGTR1 promotes lymph node metastasis in breast cancer by upregulating CXCR4/SDF-1α and inducing cell migration and invasion

The angiotensin II type I receptor (AGTR1) has a strong influence on tumor growth, angiogenesis, inflammation and immunity. However, the role of AGTR1 on lymph node metastasis (LNM) in breast cancer, which correlates with tumor progression and patient survival, has not been examined. AGTR1 was highly expressed in lymph node-positive tumor tissues, which was confirmed by the Oncomine database. Next, inhibition of AGTR1 reduced tumor growth and LNM in orthotopic xenografts by bioluminescence imaging (BLI). Losartan, an AGTR1-specific inhibitor, decreased the chemokine pair CXCR4/SDF-1α levels in vivo and inhibited AGTR1-induced cell migration and invasion in vitro. Finally, the molecular mechanism of AGTR1-induced cell migration and LNM was assessed by knocking down AGTR1 in normal cells or CXCR4 in AGTR1^high cells. AGTR1-silenced cells treated with losartan showed lower CXCR4 expression. AGTR1 overexpression caused the upregulation of FAK/RhoA signaling molecules, while knocking down CXCR4 in AGTR1^high cells downregulated these molecules. Collectively, AGTR1 promotes LNM by increasing the chemokine pair CXCR4/SDF-1α and tumor cell migration and invasion. The potential mechanism of AGTR1-mediated cell movement relies on activating the FAK/RhoA pathway. Our study indicated that inhibiting AGTR1 may be a potential therapeutic target for LNM in early-stage breast cancer.

Association of CYP11B2 gene polymorphism with preeclampsia in north east of Iran (Khorasan province)

PURPOSE

Identification the genetic factors in preeclampsia (PE) are useful to increase the current knowledge of the pathophysiology of the disorder. The genetic factors implicated for all cases of PE remain to be determined. This study was aimed to investigate association between ADD1 1378G > T, AGTR2 1675G > A, AGTR1 1166A > C, NOS3 894 G > T and CYP11B2 -344C > T gene polymorphisms in Iranian women with PE.

MATERIAL AND METHODS

117 pregnant women with PE and 103 healthy women without affected previous pregnancy by PE were selected. Genomic DNA was extracted from peripheral blood and real-time PCR was performed to investigate the polymorphisms using a commercial kit.

RESULTS

There was a significant difference in CYP11B2 -344C > T gene polymorphism between case and control groups (P = 0.025). The odds ratio was 0.71 (CI 95% = 0.28-1.79). There were no statistical significant differences between other genetic polymorphisms.

CONCLUSION

Our results showed a significant association between CYP11B2 -344C > T gene polymorphism with PE. This finding suggests that mentioned polymorphism may be associated with susceptibility to PE at least in IRAN.

The Polymorphism at the microRNA-155 Binding Site in the AGTR1 Gene is not Significantly Associated with Rheumatic Heart Disease in Saudi Arabia Population

BACKGROUND

Rheumatic Heart Disease (RHD) remains a major cause of cardiovascular diseases and the most devastating effects are shown on children and young adults. RHD is caused due to the interaction between microbial, environmental, immunologic, and genetic factors. The Renin- Angiotensin Aldosterone System (RAAS) has been strongly implicated as the susceptibility pathway in the pathogenesis of the cardiovascular disease.

OBJECTIVE

The present study investigated the modulating effect of Angiotensin II type 1 receptor (AGTR1) 1166A>C polymorphism on the RHD and its clinical features in Saudi Arabia.

METHODS

AGTR1 1166A>C polymorphism was genotyped in 96 echocardiographically confirmed RHD patients and 142 ethnically matched controls by the TaqMan allelic discrimination method.

RESULTS

Genotype distribution of the AGTR1 1166A>C polymorphism was not significantly different between RHD and control groups. Furthermore, AGTR1 1166A>C genotypes are not associated with the clinical features of RHD. These data support that there was no evidence for an association between AGTR1 1166A>C polymorphism and RHD in Saudi Arabia.

CONCLUSION

To the best of our knowledge, this is the first study that has investigated the possible association between AGTR1 1166A>C polymorphism and susceptibility to RHD and its clinical features. Even though the AGTR1 gene, 1166A>C (rs5186), was reported to be associated with hypertension, left ventricular hypertrophy and coronary heart disease. The present study did not find any association between AGTR1 1166A>C polymorphism and RHD in Saudi Arabia. Further studies are needed to confirm our findings.

Angiotensin I-converting enzyme inhibitors/angiotensin II receptor blockers may reduce tumor recurrence in left-sided and early colorectal cancers

BACKGROUND

Angiotensin signaling is suggested to be involved in tumorigenesis, tumor proliferation, and metastases. In colorectal cancer (CRC), it was demonstrated that angiotensin I-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) may reduce the risk of CRC; however, their impact on tumor recurrence remains unknown. Therefore, in this study, we evaluated the impact of ACEIs/ARBs on tumor recurrence in CRC patients.

PATIENTS AND METHODS

We retrospectively investigated the clinicopathological data of 461 stage I-III CRC patients. We divided the patients into those who took an ACEI and/or ARB (the ACEI/ARB+ group) and those who did not (the ACEI/ARB- group), and we compared the two groups' recurrence-free survival (RFS) using a Kaplan-Meier curve analysis and log rank test. We also examined the impact of AGTR1 expression on tumor recurrence, using two public CRC datasets.

RESULTS

The Kaplan-Meier curves showed a trend toward improved RFS in the ACEI/ARB+ group versus the ACEI/ARB- group (p = 0.063). Subgroup analyses demonstrated that the RFS was significantly better in the ACEI/ARB+ group versus the ACEI/ARB- group in the patients with left-sided CRC (p = 0.030) and those with stage I CRC (p = 0.009). Consistent with these findings, the AGTR1 expression was higher in the left-sided versus right-sided colon (p = 0.048). High AGTR1 expression levels were associated with poor RFS in the GSE39582 dataset's stage I-III CRC patients (p < 0.001), and this finding was also validated in the GSE17536 dataset (p = 0.023).

CONCLUSION

ACEI/ARB treatment may reduce tumor recurrence in left-sided CRC and early-stage CRC.

Association of ACE I/D and AGTR1 A1166C Gene Polymorphisms and Risk of Uterine Leiomyoma: A Case-Control Study

Objective:

Uterine leiomyoma (UL) can be considered as the most common benign gynecological tumors of the smooth muscle cells in the myometrium. They are likely to be associated with infertility and recurrent abortion as well as obstructed labor and post-partum hemorrhage. Moreover, altered vascular-related genes can be linked to developing leiomyoma. Polymorphisms of the angiotensin-converting enzyme (ACE) gene are associated with some vascular diseases. The present study was carried out to investigate the association of ACE I/D and AGTR1A1166C gene polymorphisms and the risk of uterine leiomyoma in a sample of Iranian population.

Methods:

The study was carried out on a total of 413 women divided into 202 patients with diagnosed uterine leiomyomas and a control group of 211. Genotyping was performed using the PCR or PCR-RFLP methods.

Results:

The ID and DD genotypes of ACE I/D polymorphism were associated with 2 and 2.9 fold higher risk of UL compared to II genotype (OR, 2 [95% CI, 1.3 to 3.2]; P = 0.004 and OR, 2.9 [95% CI, 1.6 to 5]; P = 0.0002). The frequencies of ACE D alleles were 53.7% in women with UL and 40.3% in controls, which were observed to be statistically different (P < 0.0001). The alleles and genotypes of AGTR1 A1166C polymorphism were not different between UL and control women (P=0.9).

Conclusion:

The ACE ID and DD genotypes were associated with a higher risk of UL. No relationship was found between AGTR1A1166C polymorphism and UL.

Genetic polymorphisms associated with the prevalence of retinal vein occlusion in a Greek population

PURPOSE

To investigate possible associations of single-nucleotide polymorphisms (SNPs) from five genes with branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO).

METHODS

A total of 69 patients with retinal vein occlusion-RVO (24 with BRVO and 45 with CRVO), and 82 controls, were enrolled in this study. All subjects were screened for hypertension, diabetes mellitus, hyperlipidemia, glaucoma, anticoagulant medication, smoking status and history of stroke. The genotyping of AGTR1-A1166C, adiponectin + 276 G/T, MMP2-1306C/T, Gpla/lla-C807T/G873A and VKORC1-G1639A polymorphisms was performed using restriction fragment length polymorphism or allele-specific polymerase chain reaction.

RESULTS

The percentage of the AGTR1-A1166C C allele carriers and Gpla/lla-C807T/G873A T/A carriers was significantly higher in the CRVO patients than in the controls (P = 0.00001 and P = 0.0004, respectively). At the multiple logistic regression analysis, the AGTR1-A1166C C allele carrier status and the Gpla/lla-C807T/G873A T/A allele carrier status were found to be associated with an increased risk of CRVO. Moreover, adiponectin + 276 G/T T allele carriers had a significantly increased risk of RVO in subjects ≥ 75 years old. There was no significant difference between the BRVO patients and controls concerning the genotype or the allele frequency distributions of these SNPs. The genotype distributions or allelic frequencies of the other evaluated polymorphisms did not significantly differ between the patients with RVO and the control subjects.

CONCLUSIONS

AGTR1 A1166C and Gpla/lla C807T/G873A polymorphisms are likely to be risk factors for CRVO. Adiponectin + 276 G/T SNP is likely to predispose to RVO in older subjects.

Improvements of symptoms of Alzheimer`s disease by inhibition of the angiotensin system

With ageing of the global society, the frequency of ageing-related neurodegenerative diseases such as Alzheimer`s disease (AD) is on the rise worldwide. Currently, there is no cure for AD, and the four drugs approved for AD only have very small effects on AD symptoms. Consequently, there are enormous efforts worldwide to identify new targets for treatment of AD. Approaches that interfere with classical neuropathologic features of AD, such as extracellular senile plaques formed of aggregated amyloid-beta (Abeta), and intracellular neurofibrillary tangles of hyperphosphorylated tau have not been successful so far. In search for a treatment approach of AD, we found that inhibition of the angiotensin-converting enzyme (ACE) by a centrally acting ACE inhibitor retards symptoms of neurodegeneration, Abeta plaque formation and tau hyperphosphorylation in experimental models of AD. Our approach is currently being investigated in a clinical setting. Initial evidence with AD patients shows that a brain-penetrating ACE inhibitor counteracts the process of neurodegeneration and dementia. Moreover, centrally acting ACE inhibitors given in addition to the standard therapy, cholinesterase inhibition, can improve cognitive function of AD patients for several months. This is one of the most promising results for AD treatment since more than a decade.

Increased Reactive Oxygen Species Generation Contributes to the Atherogenic Activity of the B2 Bradykinin Receptor

Atherosclerosis and ensuing cardiovascular disease are major causes of death with insufficient treatment options. In search for pathomechanisms of atherosclerosis, we investigated the impact of the B2 bradykinin receptor, Bdkrb2, on atherosclerotic lesion formation, because to date it is not clear whether the B2 bradykinin receptor is atheroprotective or atherogenic. As a model of atherosclerosis, we used hypercholesterolemic ApoE-deficient (apolipoprotein E-deficient) mice, which develop atherosclerotic lesions in the aorta with increasing age. The role of Bdkrb2 in atherosclerosis was studied in ApoE-deficient mice, which were either Bdkrb2-deficient, or had moderately increased aortic B2 bradykinin receptor protein levels induced by transgenic BDKRB2 expression under control of the ubiquitous CMV promoter. We found that Bdkrb2 deficiency led to a significantly decreased atherosclerotic plaque area whereas transgenic BDKRB2 expression enhanced atherosclerotic lesion formation in the aorta of ApoE-deficient mice at an age of 8 months. Concomitantly, the aortic content of reactive oxygen species (ROS) was higher in BDKRB2-expressing mice whereas Bdkrb2 deficiency decreased aortic ROS levels of ApoE-deficient mice. In addition, aortic nitrate as a marker of nitric oxide activity and the endothelial nitric oxide synthase (eNOS) co-factor, tetrahydrobiopterin (BH4) were reduced in BDKRB2-expressing ApoE-deficient mice. The decreased aortic BH4 content could be a consequence of increased ROS generation and down-regulated aortic expression of the BH4-synthesizing enzyme, Gch1 (GTP cyclohydrolase 1). In agreement with a causal involvement of decreased BH4 levels in the atherogenic function of BDKRB2, we found that treatment with the BH4 analog, sapropterin, significantly retarded atherosclerotic plaque formation in BDKRB2-expressing ApoE-deficient mice. Together our data show that the B2 bradykinin receptor is atherogenic, and the atherosclerosis-promoting function of BDKRB2 is partially caused by decreased aortic BH4 levels, which could account for eNOS uncoupling and further enhancement of ROS generation.

Sensitization of the Angiotensin II AT1 Receptor Contributes to RKIP-Induced Symptoms of Heart Failure

Inhibition of the G-protein-coupled receptor kinase 2 (GRK2) is an emerging treatment approach for heart failure. Therefore, cardio-protective mechanisms induced by GRK2 inhibition are under investigation. We compared two different GRK2 inhibitors, i.e., (i) the dual-specific GRK2 and raf kinase inhibitor protein, RKIP, and (ii) the dominant-negative GRK2-K220R mutant. We found that RKIP induced a strong sensitization of Gq/11-dependent, heart failure-promoting angiotensin II AT1 receptor signaling. The AT1-sensitizing function of RKIP was mediated by the RKIP-GRK2 interaction because the RKIP-S153V mutant, which does not interact with GRK2, had no effect on AT1-stimulated signaling. In contrast, GRK2-K220R significantly inhibited the AT1-stimulated signal. The in vivo relevance of these major differences between two different approaches of GRK2 inhibition was analyzed by generation of transgenic mice with myocardium-specific expression of RKIP and GRK2-K220R. Our results showed that a moderately increased cardiac protein level of RKIP was sufficient to induce major symptoms of heart failure in aged, 8-months-old RKIP-transgenic mice in two different genetic backgrounds. In contrast, GRK2-K220R protected against chronic pressure overload-induced cardiac dysfunction. The AT1 receptor contributed to RKIP-induced heart failure because treatment with the AT1 receptor antagonist, losartan, retarded symptoms of heart failure in RKIP-transgenic mice. Thus, sensitization of the heart failure-promoting AT1 receptor by the RKIP-GRK2 interaction contributes to heart failure whereas dominant-negative GRK2-K220R is cardioprotective. Because RKIP is up-regulated on cardiac biopsy specimens of heart failure patients, the deduced heart failure-promoting mechanism of RKIP could also be relevant for the human disease.

Beta-Arrestin1 Prevents Preeclampsia by Downregulation of Mechanosensitive AT1-B2 Receptor Heteromers

Preeclampsia is the most frequent pregnancy-related complication worldwide with no cure. While a number of molecular features have emerged, the underlying causal mechanisms behind the disorder remain obscure. Here, we find that increased complex formation between angiotensin II AT1 and bradykinin B2, two G protein-coupled receptors with opposing effects on blood vessel constriction, triggers symptoms of preeclampsia in pregnant mice. Aberrant heteromerization of AT1-B2 led to exaggerated calcium signaling and high vascular smooth muscle mechanosensitivity, which could explain the onset of preeclampsia symptoms at late-stage pregnancy as mechanical forces increase with fetal mass. AT1-B2 receptor aggregation was inhibited by beta-arrestin-mediated downregulation. Importantly, symptoms of preeclampsia were prevented by transgenic ARRB1 expression or a small-molecule drug. Because AT1-B2 heteromerization was found to occur in human placental biopsies from pregnancies complicated by preeclampsia, specifically targeting AT1-B2 heteromerization and its downstream consequences represents a promising therapeutic approach.

Non-radioactive binding assay for bradykinin and angiotensin receptors

G protein-coupled receptors (GPCRs) are the largest family of membrane protein playing an important role in cellular signal transduction. GPCRs interact with different molecules acting as ligands capable to trigger responses on signaling pathway. Those molecules present specific binding profiles in which, usually, are determined by methods based on radioactive labeled ligands. Here we present an alternative method based on time-resolved fluorescent labeled ligand, specific customized for angiotensin II receptors (AGTR1 and AGTR2) and kinin receptors (BDKRB1 and BDKRB2) wherein, their natural ligands were labeled with the lanthanide europium to generate the Eu³⁺-N1-DTT-ligands (AngII, BK, and DBK). Competitive binding profile is determined with a fixed concentration of labeled ligand competing with variable concentrations (10^-5 to 10^-12) of unlabeled ligand. This method is capable to determine binding profiles with comparable results with traditional one and present a reliable alternative to radioactive based methods usage.

Qiliqiangxin Rescues Mouse Cardiac Function by Regulating AGTR1/TRPV1-Mediated Autophagy in STZ-Induced Diabetes Mellitus

BACKGROUND/AIMS

To explore the potential role of qiliqiangxin (QLQX) A traditional Chinese medicine and the involvement of angiotensin II receptor type 1 (AGTR1) and transient receptor potential vanilloid 1 (TRPV1) in diabetic mouse cardiac function.

METHODS

Intragastric QLQX was administered for 5 weeks after streptozotocin (STZ) treatment. Additionally, Intraperitoneal injections of angiotensin II (Ang II) or intragastric losartan (Los) were administered to assess the activities of AGTR1 and TRPV1. Two-dimensional echocardiography and tissue histopathology were used to assess cardiac function Western blot was used to detect the autophagic biomarkers Such as light chain 3 P62 and lysosomal-associated membrane protein 2 And transmission electron microscopy was used to count the number of autophagosomes.

RESULTS

Decreased expression of TRPV1 and autophagic hallmarks and reduced numbers of autophagolysosomes as well as increased expression of angiotensin converting enzyme 1 and AGTR1 were observed in diabetic hearts. Blocking AGTR1 with Los mimicked the QLQX-mediated improvements in cardiac function Alleviated myocardial fibrosis and enabled autophagy Whereas Ang II abolished the beneficial effects of QLQX in wild type diabetic mice but not in TRPV1-/- diabetic mice.

CONCLUSIONS

QLQX may improve diabetic cardiac function by regulating AGTR1/ TRPV1-mediated autophagy in STZ-induced diabetic mice.

Angiotensin II receptor 1 gene variants are associated with high-altitude pulmonary edema risk

Previous studies demonstrated that Angiotensin II Receptor 1 (AGTR1) may play an important role in the development of high-altitude pulmonary edema. We envisaged a role for AGTR1 gene variants in the pathogenesis of HAPE and investigated their potential associations with HAPE in a Han Chinese population. We genotyped seven AGTR1 polymorphisms in 267 patients with diagnosed HAPE and 304 controls and evaluated their association with risk of HAPE. Statistically significant associations were found for the single nucleotide polymorphisms (SNPs) rs275651 (p = 0.017; odds ratio [OR] = 0.65) and rs275652 (p = 0.016; OR = 0.64). Another SNP rs10941679 showed a marginally significant association after adjusting for age and sex in the additive genetic model (adjusted OR = 1.44, 95% CI = 1.01-2.04, p = 0.040). Haplotype analysis confirmed that the haplotype "AG" was associated with a 35% reduction in the risk of developing HAPE, while the haplotype "AA" increased the risk of developing HAPE by 44%. These results provide the first evidence linking genetic variations in AGTR1 with HAPE risk in Han Chinese individuals.

Interactions Between PPARG and AGTR1 Gene Polymorphisms on the Risk of Hypertension in Chinese Han Population

AIMS

To explore the interactions between PPARG and AGTR1 polymorphisms and their associations with hypertension in the Chinese Han population.

METHODS

Seven single nucleotide polymorphisms (SNPs) of the PPARG gene and five SNPs of the AGTR1 gene were selected and genotyped in 1591 unrelated Chinese Han adults. The SNPAssoc package of R was used to analyze the associations between the selected SNPs and hypertension. The potential gene-gene interactions between PPARG and AGTR1 genes were tested by model-based multifactor dimensionality reduction (MB-MDR).

RESULTS

The frequencies of the C allele of rs3856806 and the G allele of rs13433696 in the PPARG gene were significantly lower in hypertensive subjects, whereas the A allele of rs9817428 in the PPARG gene was much higher in hypertensives. In addition, individuals with T allele of rs2933249 in the AGTR1 gene displayed a significantly decreased risk of hypertension. MB-MDR analyses suggested that the two-locus model (rs9817428 and rs2933249) and the three-locus model (rs9817428, rs3856806, and rs2933249) were significantly associated with a decreased risk of hypertension. Moreover, among the eight SNPs not individually associated with hypertension (rs12631819, rs2920502, rs1175543, and rs2972164 in the PPARG gene, and rs2638360, rs1492100, rs5182, and rs275646 in the AGTR1 gene), the two-locus model involving rs12631819 and rs5182 demonstrated increased susceptibility to hypertension, and the five-locus model involving rs12631819, rs2920502, rs2972164, rs5182, and rs2638360 demonstrated a significantly decreased risk of hypertension.

CONCLUSION

Polymorphisms in both the PPARG and AGTR1 genes were found to be significantly associated with hypertension. Moreover, there were significant gene-gene interactions identified between the PPARG and AGTR1 genes in relation to hypertension susceptibility in the Chinese Han population.

The association of renin-angiotensinogen system genes polymorphisms and idiopathic recurrent pregnancy loss

The most common complication of pregnancy is idiopathic recurrent pregnancy loss (RPL). To identify the contribution of gene polymorphisms to this condition, we evaluated the association between RPL and the angiotensinogen (AGT), angiotensin receptor 1 (AGTR1) and Angiotensinogen converting enzyme (ACE). In this case-control study, the frequency of AGT (rs4762 and rs699), AGTR1 (rs5186) and ACE insertion/deletion (rs4340) polymorphisms in 202 idiopathic RPL women was compared with 210 women with no history of abortion, using tetra-primer ARMS-PCR. Polymorphisms were analysed by logistic regression analysis according to inheritance models. The CT genotype of AGT rs4762, the CC genotype of AGT rs699 and the AC genotype of AGTR1 rs5186 in a co-dominant inheritance model were associated with idiopathic RPL (OR = 1.63, 95% CI = 1.07-2.49 of CT versus CC; OR = 5.97, 95% CI = 1.28-27.82 of CC versus TT; and OR = 1.99, 95% CI = 1.22-3.07 of AC versus AA). The allele frequency of AGT rs699 and AGTR1 rs5186 polymorphisms, but not AGT rs4762 and ACE rs4340 polymorphisms were significantly different between women with RPL patients and controls (p = 0.020, p = 0.003, p = 0.105 and p = 0.065, respectively). These results show that there is a significant relationship between AGT (rs699) and AGTR1 (rs5186) polymorphisms and idiopathic RPL in the Iranian population.

RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis

Liver fibrosis, leading to cirrhosis and liver failure, can occur after chronic liver injury. The transition of hepatic stellate cells (HSCs) from quiescent cells into proliferative and fibrogenic cells is a central event in liver fibrosis. Here, we show that RAS protein activator like-1 (RASAL1), a RAS-GTPase-activating protein, which switches off RAS activity, is significantly decreased during HSC activation, and that HSC activation can be antagonized by forced expression of the RASAL1 protein. We demonstrate that RASAL1 suppresses HSC proliferation by regulating the Ras-MAPK pathway, and that RASAL1 suppresses HSC fibrogenic activity by regulating the PKA-LKB1-AMPK-SRF pathway by interacting with angiotensin II receptor, type 1. We also show that RASAL1-deficient mice are more susceptible to liver fibrosis. These data demonstrate that deregulated RASAL1 expression levels and the affected downstream intracellular signaling are central mediators of perpetuated HSC activation and fibrogenesis in the liver.

Further investigation of a quantitative trait locus for ascites on chromosome 9 in broiler chicken lines

Previously, we reported a genome wide association study (GWAS) that had shown association of a region between 11.8 and 13.6 Mbp on chromosome 9 with ascites phenotype in broilers. We had used microsatellite loci to demonstrate an association of particular genotypes for this region with ascites in experimental ascites lines and commercial broiler breeder lines. We identified two potential candidate genes, AGTR1 and UTS2D, within that chromosomal region for mediating the quantitative effect. We have now extended our analysis using SNPs for these genes to assess association with resistance or susceptibility to ascites in these same broiler lines. Surprisingly, in contrast to our previous GWAS and microsatellite data for this region, we find no association of the SNP genotypes or haplotypes in the region suggesting that the two genes might have limited association with the disease phenotype.

Association and Interaction Effect of AGTR1 and AGTR2 Gene Polymorphisms with Dietary Pattern on Metabolic Risk Factors of Cardiovascular Disease in Malaysian Adults

Gene-diet interaction using a multifactorial approach is preferred to study the multiple risk factors of cardiovascular disease (CVD). This study examined the association and gene-diet interaction effects of the angiotensin II type 1 receptor (AGTR1) gene (rs5186), and type 2 receptor (AGTR2) gene (rs1403543) polymorphisms on metabolic risk factors of CVD in Malaysian adults. CVD parameters (BMI, blood pressure, glycated hemoglobin, total cholesterol (TC), triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), and TC/HDL-C ratio), and constructed dietary patterns “vegetables, fruits, and soy diet” (VFSD), and “rice, egg, and fish diet” (REFD) were obtained from previous studies. Genotyping analysis was performed by real-time PCR using Taqman probes. The subjects were 507 adults (151 Malays; 179 Chinese; and 177 Indians). Significant genetic associations were obtained on blood lipids for rs5186 in Malays and Chinese, and rs1403543 in Chinese females. The significant gene-diet interaction effects after adjusting for potential confounders were: rs5186 × VFSD on blood pressure in Malays (p = 0.016), and in Chinese on blood lipids for rs5186 × REFD (p = 0.009–0.023), and rs1403543 × VFSD in female subjects (p = 0.001–0.011). Malays and Chinese showed higher risk for blood pressure and/or lipids involving rs5186 and rs1403543 SNPs together with gene-diet interactions, but not Indians.

Association of renin-angiotensin-aldosterone system gene polymorphisms with left ventricular hypertrophy in patients with heart failure with preserved ejection fraction: A case-control study

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) has close ties with hypertension, though risk factors to the development of HFpEF in hypertensive patients are not fully understood. Left ventricular hypertrophy (LVH) signifies the susceptibility toward diastolic heart dysfunction, and genetic determinants of LVH as a result may serve as risk predictors for HFpEF in hypertension. We investigated the role of three renin-angiotensin-aldosterone system (RAAS) gene polymorphisms in the development of LVH in hypertensive patients with a diagnosis of HFpEF.

METHODS

A total of 176 hypertensive patients with a diagnosis of HFpEF were divided to cases with LVH and controls without. rs4343 and rs4291 of angiotensin-converting enzyme (ACE) and rs5186 of angiotensin receptor type 1 were genotyped using PCR-RFLP method.

RESULTS

Genotypes and allele frequencies were significantly different between the case and control groups for rs4343 and rs4291, whereas no difference was observed for rs5186.

CONCLUSION

Increased ACE activity explains the significant association of rs4343 and rs4291 polymorphisms with LVH in the carriers. Furthermore, findings support the pathophysiologic links between RAAS and increased LV mass in hypertension and suggest a genetic susceptibility to HFpEF. Such polymorphisms may serve as risk predictors of HFpEF in hypertensive patients.

Hypomethylation of the Angiotensin II Type I Receptor (AGTR1) Gene Along with Environmental Factors Increases the Risk for Essential Hypertension

OBJECTIVES

The present study aimed to evaluate the hypertension status of community residents, analyze environmental and epigenetic factors, and propose prevention measures for hypertension.

METHODS

In our study, different methylation levels were distinguished utilizing melting temperature (Tm) values in both the case and the control group. Multiple logistic regression analysis was used to estimate the risk of having essential hypertension (EH) between hypertensive and nonhypertensive participants. A receiver-operating characteristic curve was used to analyze Tm cutoff levels of methylation.

RESULTS

The average DNA Tm was 71.784 with a standard deviation of 0.210. The Tm value of community residents (Fujian, China) was inversely correlated with systolic and diastolic blood pressure. Student t test analysis showed a clear separation in Tm expression levels between the hypertensive and the control group (p < 0.05). The Tm value was lower in the hypertension group than in the normotensive group. Multivariate regression analysis showed that high levels of DNA methylation were a protective factor in hypertension with adjustment of demographic and environmental factors, whereas when the Tm value increased by 0.1 units, the risk of hypertension was reduced by 0.652 times. Patients that smoked and consumed an irregular diet demonstrated a lower degree of methylation in the presence of hypertension.

CONCLUSIONS

DNA methylation affects the risk for the development of hypertension; therefore, epigenetic markers could be used to measure hypertension levels to help elucidate the pathogenesis of EH.

The miR-34a-5p promotes the multi-chemoresistance of osteosarcoma via repression of the AGTR1 gene

Background

Chemoresistance hinders the curative cancer chemotherapy. MicroRNAs (miRNAs) are key players in diverse biological processes including the chemoresistance of cancers.

Methods

A RNA-seq-based miR-omic analysis of osteosarcoma (OS) cells was performed to detect the levels of miR-34a-5p. Bioinformatics analysis revealed that AGTR1 is one of the target genes of miR-34a-5p. The mRNA and protein levels of AGTR1 were detected in both the miR-34a-5p-mimic transfected G-292 and miR-34a-5p-antagomiR transfected SJSA-1 cells. The involvement of AGTR1 with OS chemoresistance was validated by the experiments with siRNA-mediated repression or overexpression of the AGTR1 gene.

Results

We showed that miR-34a-5p promotes the multi- chemoresistance of OS. The angiotensin II type 1 receptor (AGTR1) gene, is one of the targets of miR-34a-5p in OS and thus negatively correlates with OS chemoresistance by systematic investigations of a multi-drug sensitive (G-292) and resistant (SJSA-1) OS cell lines. Down-regulation of the AGTR1 expression by siRNA passivates G-292 cells and suppresses cell apoptosis, while over-expression of AGTR1 sensitizes SJSA-1 cells and thus promotes the drug-triggered cell death.

Conclusions

The miR-34a-5p and its target gene AGTR1 are the potential targets for an effective chemotherapy of OS. Our results also provide novel insights into the effective chemotherapy for OS patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-3002-x) contains supplementary material, which is available to authorized users.

Estimation of the relationship between the polymorphisms of selected genes: ACE, AGTR1, TGFβ1 and GNB3 with the occurrence of primary vesicoureteral reflux

PURPOSE

Etiopathogenesis of VUR is composite and not fully understood. Many data indicate the importance of genetic predisposition. The aim of this study was to establish the relationship of selected polymorphisms: 14094 polymorphism of the ACE, polymorphism rs1800469 of TGFβ-1, rs5443 gene polymorphism of the GNB3 and receptor gene polymorphism rs5186 type 1 AGTR1 with the occurrence of the primary vesicoureteral reflux.

MATERIAL

The study included 190 children: 90 with the primary VUR confirmed with the voiding cystourethrogram and excluded secondary VUR and a control group of 100 children without a history of the diseases of the genitourinary tract.

METHODS

The study was planned in the scheme: "tested case versus control." Genomic DNA was isolated from the leukocytes of peripheral blood samples. The results were statistically analyzed in the Statistica 10 using χ ² test and analysis of the variance Anova.

RESULTS

Any of the four studied polymorphisms showed no difference in the distribution of genotypes between patients with primary vesicoureteral reflux and the control group. In patients with VUR and TT genotype polymorphism rs5443 GNB3 gene, the glomerular filtration rate was significantly higher than in patients with genotype CC or CT.

CONCLUSIONS

(1) No relationship was found between the studied polymorphisms (14094 ACE gene, rs1800469 gene TGFβ1, GNB3 gene rs5443, rs5186 AGTR1 gene) and the occurrence of primary vesicoureteral reflux. (2) TT genotype polymorphism rs5443 GNB3 gene may be a protective factor for the improved renal function in patients with primary vesicoureteral reflux in patients with genotype CC or CT.

Renin-angiotensin system gene expression and neurodegenerative diseases

Hypothesis:

Single nucleotide polymorphisms and altered gene expression of components of the renin–angiotensin system (RAS) are associated with neurodegenerative diseases.

Introduction:

Drugs that interact with the RAS have been shown to affect the course of neurodegenerative disease, suggesting that abnormalities in the RAS may contribute to neurodegenerative disease.

Materials and methods:

A meta-analysis of genome-wide association studies and gene expression data for 14 RAS-related proteins was carried out for five neurodegenerative diseases: Alzheimer’s disease, Parkinson’s disease, narcolepsy, amyotrophic lateral sclerosis and multiple sclerosis.

Results:

No single nucleotide polymorphisms in any of the 14 RAS-related protein genes were significantly associated with the five neurodegenerative diseases investigated. There was an inverse association between expression of ATP6AP2, which encodes the (pro)renin receptor, and multiple sclerosis, Alzheimer’s disease and Parkinson’s disease. An association of AGTR, which encodes the AT₁ angiotensin II receptor, and Parkinson’s disease and Alzheimer’s disease was also observed.

Conclusions:

To date, no single nucleotide polymorphisms in components of the RAS can be definitively linked to the neurodegenerative diseases evaluated in this study. However, altered gene expression of several components of the RAS is associated with several neurodegenerative diseases, which may indicate that the RAS contributes to the pathology of these diseases.

Prenatal Testosterone Exposure Decreases Aldosterone Production but Maintains Normal Plasma Volume and Increases Blood Pressure in Adult Female Rats

Plasma testosterone levels are elevated in pregnant women with preeclampsia and polycystic ovaries; their offspring are at increased risk for hypertension during adult life. We tested the hypothesis that prenatal testosterone exposure induces dysregulation of the renin-angiotensin-aldosterone system, which is known to play an important role in water and electrolyte balance and blood pressure regulation. Female rats (6 mo old) prenatally exposed to testosterone were examined for adrenal expression of steroidogenic genes, telemetric blood pressure, blood volume and Na⁺ and K⁺ levels, plasma aldosterone, angiotensin II and vasopressin levels, and vascular responses to angiotensin II and arg⁸-vasopressin. The levels of Cyp11b2 (aldosterone synthase), but not the other adrenal steroidogenic genes, were decreased in testosterone females. Accordingly, plasma aldosterone levels were lower in testosterone females. Plasma volume and serum and urine Na⁺ and K⁺ levels were not significantly different between control and testosterone females; however, prenatal testosterone exposure significantly increased plasma vasopressin and angiotensin II levels and arterial pressure in adult females. In testosterone females, mesenteric artery contractile responses to angiotensin II were significantly greater, while contractile responses to vasopressin were unaffected. Angiotensin II type-1 receptor expression was increased, while angiotensin II type-2 receptor was decreased in testosterone arteries. These results suggest that prenatal testosterone exposure downregulates adrenal Cyp11b2 expression, leading to decreased plasma aldosterone levels. Elevated angiotensin II and vasopressin levels along with enhanced vascular responsiveness to angiotensin II may serve as an underlying mechanism to maintain plasma volume and Na⁺ and K⁺ levels and mediate hypertension in adult testosterone females.

AGTR1 rs3772622 gene polymorphism increase the risk of nonalcoholic fatty liver disease patients suffer coronary artery disease in Northern Chinese Han population

Background

Cardiovascular disease (CAD) responsible and nonalcoholic fatty liver disease (NAFLD) are both metabolic diseases, and they are mostly influenced by genetic factors. The aim of our study is to evaluate the relationship between angiotensin II type-1 receptor (AGTR1) gene rs3772622 polymorphisms and the risk of developing coronary artery disease (CAD) in Chinese patients with NAFLD.

Methods

Genotype for AGTR1 rs3772622 in 574 NAFLD patients with CAD or 589 NAFLD patients without CAD, 332 CAD patients exclude NAFLD and 338 health control subjects were determined by sequencing and polymerase chain reaction analysis. Relevant statistical methods were employed to analyze the genotypes, alleles and the clinical date. Inter-group differences and associations were assessed statistically using t-tests and Chi square and logistic analyses. The relative risk of AGTR1 rs3772622 for NAFLD was estimated by logistic regression analysis.

Results

No significant difference in genotype and allele frequency of AGTR1 rs3772622 was found between the NAFLD without CAD population and the controls (P > 0.05). However, makeable difference was found when compared the CAD in patients with NAFLD and CAD free NAFLD patients (P < 0.001 OR = 2.09). Similarly, significant difference was found in AGTR1 rs3772622 genotype distribution between the groups of CAD patients and control (P = 0.046 OR = 1.71).

Conclusions

AGTR1 rs3772622 gene polymorphism was not associated with the risk of NAFLD, but could increase the risk of NAFLD patients suffering from CAD in the Chinese Han population. Deeply mechanisms underlying the association between AGTR1 rs3772622 gene polymorphism and the risk of CAD in NAFLD patients need more research.

Effects of zinc oxide nanoparticles on human coronary artery endothelial cells

Inhalation of zinc oxide (ZnO) metal fumes is known to cause metal fume fever and to have systemic effects; however, the effects of ZnO nanoparticles (ZnONPs) on the cardiovascular system remain unclear. The objective of this study was to investigate the cardiovascular toxicity of ZnONPs. Human coronary artery endothelial cells (HCAECs) were exposed to ZnONPs of different sizes to investigate the cell viability, 8-hydroxy-2'-deoxyguanosine (8-OHdG), interleukin (IL)-6, nitric oxide (NO), and regulation of cardiovascular disease-related genes. Exposure of HCAECs to ZnONPs resulted in decreased cell viability and increased levels of 8-OHdG, IL-6, and NO. Downregulation of cardiovascular-associated genes was observed in response to ZnONPs in HCAECs determined by qPCR, suggesting that the calcium signaling pathway, neuroactive ligand-receptor interaction, hypertrophic cardiomyopathy, dilated cardiomyopathy, and renin-angiotensin system are important affected pathways in response to ZnONPs. Furthermore, we observed a significant response of AGTR1 to ZnONP exposure in HCAECs. Our results suggest that ZnONPs cause toxicity to HCAECs, which could be associated with cardiovascular dysfunction.

Overexpression of angiotensin II type 1 receptor in breast cancer cells induces epithelial-mesenchymal transition and promotes tumor growth and angiogenesis

The angiotensin II type I receptor (AGTR1) has been implicated in diverse aspects of human disease, from the regulation of blood pressure and cardiovascular homeostasis to cancer progression. We sought to investigate the role of AGTR1 in cell proliferation, epithelial-mesenchymal transition (EMT), migration, invasion, angiogenesis and tumor growth in the breast cancer cell line MCF7. Stable overexpression of AGTR1 was associated with accelerated cell proliferation, concomitant with increased expression of survival factors including poly(ADP-ribose) polymerase (PARP) and X-linked inhibitor of apoptosis (XIAP), as well as extracellular signal-regulated kinase (ERK) activation. AGTR1-overexpressing MCF7 cells were more aggressive than their parent line, with significantly increased activity in migration and invasion assays. These observations were associated with changes in EMT markers, including reduced E-cadherin expression and increased p-Smad3, Smad4 and Snail levels. Treatment with the AGTR1 antagonist losartan attenuated these effects. AGTR1 overexpression also accelerated tumor growth and increased Ki-67 expression in a xenograft model. This was associated with increased tumor angiogenesis, as evidenced by a significant increase in microvessels in the intratumoral and peritumoral areas, and enhanced tumor invasion, with the latter response associated with increased EMT marker expression and matrix metallopeptidase 9 (MMP-9) upregulation. In vivo administration of losartan significantly reduced both tumor growth and angiogenesis. Our findings suggest that AGTR1 plays a significant role in tumor aggressiveness, and its inhibition may have therapeutic implications.

Role and therapeutic potential of G-protein coupled receptors in breast cancer progression and metastases

G-protein-coupled receptors (GPCRs) comprise a large family of cell-surface receptors, which have recently emerged as key players in tumorigenesis, angiogenesis and metastasis. In this review, we discussed our current understanding of the many roles played by GPCRs in general, and particularly Angiotensin II type I receptor (AGTR1), a member of the seven-transmembrane-spanning G-protein coupled receptor superfamily, and its significance in breast cancer progression and metastasis. We have also discussed different strategies for targeting AGTR1, and its ligand Angiotension II (Ang II), which might unravel unique opportunities for breast cancer prevention and treatment. For example, AGTR1 blockers (ARBs) which are already in clinical use for treating hypertension, merit further investigation as a therapeutic strategy for AGTR1-positive cancer patients and may have the potential to prevent Ang II-AGTR1 signalling mediated cancer pathogenesis and metastases.