Angiotensinogen Expression Research Articles

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

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

CRISPR/Cas9 Mediated Deletion of the Angiotensinogen Gene Reduces Hypertension: A Potential for Cure?

[Figure: see text].

Klotho supplementation attenuates blood pressure and albuminuria in murine model of IgA nephropathy.

Klotho interacts with various membrane proteins, such as transforming growth factor-β (TGFβ) and insulin-like growth factor (IGF) receptors. The renal expression of klotho is diminished in chronic kidney disease. In this study, we assessed the effects of klotho supplementation on a murine model of IgA nephropathy. Twenty-four-week-old hyper serum IgA (HIGA) mice were subcutaneously injected daily with recombinant human klotho protein (20 μg/kg per day) or the vehicle. After 2 months, the mice were killed using an anesthesia overdose and their kidneys were harvested for analysis. Supplementation of exogenous klotho protein reduced SBP, albuminuria, 8-epi-prostaglandin F2α excretion, glomerular filtration rate, renal angiotensin II concentration, and angiotensinogen expression in HIGA mice. Additionally, it enhanced renal expression of superoxide dismutase (SOD) and renal klotho itself. The findings using laser-manipulated microdissection demonstrated that klotho supplementation reduced the glomerular expression of TGFβ, fibronectin, and IGF, and increased the glomerular expression of connexin (Cx) 40. These results indicate that klotho supplementation reduces blood pressure by suppressing the renin--angiotensin system in HIGA mice. Klotho inhibits IGF signaling to preserve glomerular Cx40 levels, ameliorating albuminuria in HIGA mice. Klotho protein supplementation attenuates mesangial expansion by inhibiting TGFβ signaling in HIGA mice.

Effects of carotid baroreceptor stimulation on aortic remodeling in obese rats

Background and aimOur previous study found carotid baroreceptor stimulation (CBS) reduces body weight and white adipose tissue (WAT) weight, restores abnormal secretion of adipocytokines and inflammation factors, decreases systolic blood pressure (SBP) by inhibiting activation of sympathetic nervous system (SNS) and renin-angiotensin system (RAS) in obese rats. In this study, we explore effects of CBS on aortic remodeling in obese rats. Methods and resultsRats were fed high-fat diet (HFD) for 16 weeks to induce obesity and underwent either CBS device implantation and stimulation or sham operation at 8 weeks. BP and body weight were measured weekly. RAS activity of WAT, histological, biochemical and functional profiles of aortas were detected after 16 weeks. CBS effectively decreased BP in obese rats, downregulated mRNA expression of angiotensinogen (AGT) and renin in WAT, concentrations of AGT, renin, angiotensin II (Ang II), protein levels of Ang II receptor 1 (AT1R) and Ang II receptor 2 (AT2R) in WAT were declined. CBS inhibited reactive oxygen species (ROS) generation, inflammatory response and endoplasmic reticulum (ER) stress in aortas of obese rats, restrained vascular wall thickening and vascular smooth muscle cells (VSMCs) phenotypic switching, increased nitric oxide (NO) synthesis, promoted endothelium-dependent vasodilatation by decreasing protein expression of AT1R and leptin receptor (LepR), increasing protein expression of adiponectin receptor 1 (AdipoR1) in aortic VSMCs. ConclusionCBS reduced BP and reversed aortic remodeling in obese rats, the underlying mechanism might be related to the suppressed SNS activity, restored adipocytokine secretion and restrained RAS activity of WAT.

Parathyroid hormone type 1 receptor regulates osteosarcoma K7M2 Cell growth by interacting with angiotensinogen.

This study aimed to determine the interactions between parathyroid hormone type 1 receptor (PTHR1) and angiotensinogen (AGT) and the effects of these agents on osteosarcoma (OS). We constructed a stably transfected mouse OS K7M2 cell line (shPTHR1‐ K7M2) using shRNA and knocked down AGT in these cells using siRNA‐AGT. The transfection efficiency and expression of AGT, chemokine C‐C motif receptor 3 (CCR3), and chemokine (C‐C motif) ligand 9 (CCL9) were determined using real‐time quantitative PCR. Cell viability and colony formation were assessed using Cell Counting Kit‐8 and crystal violet staining, respectively. Cell apoptosis and cycle phases were assessed by flow cytometry, and cell migration and invasion were evaluated using Transwell assays. Interference with PTHR1 upregulated the expression of AGT and CCR3, and downregulated that of CCL9, which was further downregulated by AGT knockdown. Cell viability, migration, invasion and colony formation were significantly decreased, while cell apoptosis was significantly increased in shPTHR1‐K7M2, compared with those in K7M2 cells (P < .05 for all). However, AGT knockdown further inhibited cell viability after 72 h of culture but promoted cell migration and invasion. PTHR1 interference decreased and increased the numbers of cells in the G0/G1 and G2/M phases, respectively, compared with those in K7M2 cells. Angiotensinogen knockdown increased the number of cells in the G0/G1 phase compared with that in the shPTHR1‐K7M2 cells. Therefore, PTHR1 affects cell viability, apoptosis, migration, invasion and colony formation, possibly by regulating AGT/CCL9 in OS cells.

Cancer Stem Cells in Metastatic Head and Neck Cutaneous Squamous Cell Carcinoma Express Components of the Renin-Angiotensin System.

We investigated the expression of components of the renin-angiotensin system (RAS) by cancer stem cell (CSC) subpopulations in metastatic head and neck cutaneous squamous cell carcinoma (mHNcSCC). Immunohistochemical staining demonstrated expression of prorenin receptor (PRR), angiotensin-converting enzyme (ACE), and angiotensin II receptor 2 (AT2R) in all cases and angiotensinogen in 14 cases; however, renin and ACE2 were not detected in any of the 20 mHNcSCC tissue samples. Western blotting showed protein expression of angiotensinogen in all six mHNcSCC tissue samples, but in none of the four mHNcSCC-derived primary cell lines, while PRR was detected in the four cell lines only. RT-qPCR confirmed transcripts of angiotensinogen, PRR, ACE, and angiotensin II receptor 1 (AT1R), but not renin or AT2R in all four mHNcSCC tissue samples and all four mHNcSCC-derived primary cell lines, while ACE2 was expressed in the tissue samples only. Double immunohistochemical staining on two of the mHNcSCC tissue samples showed expression of angiotensinogen by the SOX2+ CSCs within the tumor nests (TNs), and immunofluorescence showed expression of PRR and AT2R by the SOX2+ CSCs within the TNs and the peritumoral stroma (PTS). ACE was expressed on the endothelium of the tumor microvessels within the PTS. We demonstrated expression of angiotensinogen by CSCs within the TNs, PRR, and AT2R by the CSCs within the TNs and the PTS, in addition to ACE on the endothelium of tumor microvessels in mHNcSCC.

RETRACTED: Two transition metal coordination polymers: Magnetic properties and treatment activity on the chronic renal failure by reducing the expression of the MCP-1 and angiotensinogen in the renal endothelial cells

• Two new coordination polymers were prepared. • There is antiferromagnetic coupling between neighboring metal ions in the two compounds. • Their treatment activity on the chronic renal failure was assessed, and associated mechanism was discussed. Two new coordination polymers based on the transition-metal centers namely, {[Co(L)]•DMF} n ( 1 ) and {[Cu 2 (L) 2 ]•DMF} n ( 2 ) have been established via reaction of a bi-functional ligand 4-{bis(4-benzoic)amino}-4 H -1,2,4-triazole (H 2 L) with corresponding metal salts in a mixed solvent system of DMF and H 2 O. The structural analysis results show that the complex 1 belongs to the P 2 1 2 1 2 1 space group with a (6,6)-connected nia -type net and the complex 2 is locates in the monoclinic space group of P 2 1 / n with a novel (5,5,6,6)-connected network. Magnetic investigations have indicated that there is antiferromagnetic coupling between neighboring metal ions in the two compounds. Their treatment activity on the chronic renal failure was assessed, and associated mechanism was discussed. Firstly, the determination of 24-hour urine protein was conducted to evaluate the protective activity of the new compounds. Then, the angiotensinogen expression and the monocyte chemoattractant protein-1 (MCP-1) expression in the renal endothelial cells was determined via the real time reverse transcription polymerase chain reaction.

Male fetal sex affects uteroplacental angiogenesis in growth restriction mouse model†.

Abnormally increased angiotensin II activity related to maternal angiotensinogen (AGT) genetic variants, or aberrant receptor activation, is associated with small-for-gestational-age babies and abnormal uterine spiral artery remodeling in humans. Our group studies a murine AGT gene titration transgenic (TG; 3-copies of the AGT gene) model, which has a 20% increase in AGT expression mimicking a common human AGT genetic variant (A[-6]G) associated with intrauterine growth restriction (IUGR) and spiral artery pathology. We hypothesized that aberrant maternal AGT expression impacts pregnancy-induced uterine spiral artery angiogenesis in this mouse model leading to IUGR. We controlled for fetal sex and fetal genotype (e.g., only 2-copy wild-type [WT] progeny from WT and TG dams were included). Uteroplacental samples from WT and TG dams from early (days 6.5 and 8.5), mid (d12.5), and late (d16.5) gestation were studied to assess uterine natural killer (uNK) cell phenotypes, decidual metrial triangle angiogenic factors, placental growth and capillary density, placental transcriptomics, and placental nutrient transport. Spiral artery architecture was evaluated at day 16.5 by contrast-perfused three-dimensional microcomputed tomography (3D microCT). Our results suggest that uteroplacental angiogenesis is significantly reduced in TG dams at day 16.5. Males from TG dams are associated with significantly reduced uteroplacental angiogenesis from early to late gestation compared with their female littermates and WT controls. Angiogenesis was not different between fetal sexes from WT dams. We conclude that male fetal sex compounds the pathologic impact of maternal genotype in this mouse model of growth restriction.

Cell autonomous angiotensin II signaling controls the pleiotropic functions of oncogenic K-Ras

Oncogenic K-Ras (K-RasG12V) promotes senescence in normal cells but fuels transformation of cancer cells after the senescence barrier is bypassed. The mechanisms regulating this pleiotropic function of K-Ras remain to be fully established and bear high pathological significance. We find that K-RasG12V activates the angiotensinogen (AGT) gene promoter and promotes AGT protein expression in a Kruppel-like factor 6–dependent manner in normal cells. We show that AGT is then converted to angiotensin II (Ang II) in a cell-autonomous manner by cellular proteases. We show that blockade of the Ang II receptor type 1 (AT1-R) in normal cells inhibits oncogene-induced senescence. We provide evidence that the oncogenic K-Ras–induced synthesis of Ang II and AT1-R activation promote senescence through caveolin-1–dependent and nicotinamide adenine dinucleotide phosphate oxidase 2–mediated oxidative stress. Interestingly, we find that expression of AGT remains elevated in lung cancer cells but in a Kruppel-like factor 6–independent and high-mobility group AT-hook 1–dependent manner. We show that Ang II–mediated activation of the AT1-R promotes cell proliferation and anchorage-independent growth of lung cancer cells through a STAT3-dependent pathway. Finally, we find that expression of AGT is elevated in lung tumors of K-RasLA2-G12D mice, a mouse model of lung cancer, and human lung cancer. Treatment with the AT1-R antagonist losartan inhibits lung tumor formation in K-RasLA2-G12D mice. Together, our data provide evidence of the existence of a novel cell-autonomous and pleiotropic Ang II–dependent signaling pathway through which oncogenic K-Ras promotes oncogene-induced senescence in normal cells while fueling transformation in cancer cells.

Perivascular adipose tissue from the internal mammary artery in patients with severe coronary artery atherosclerosis.

he internal mammary artery (IMA) is routinely used as an arterial graft for coronary artery bypass grafting with an excellent long‑term patency rate, but its protective mechanism is unclear. We evaluated the differences between the expression of several gene in perivascular adipose tissue from the IMA (PVAT‑IMA) as compared with other fat depots in patients with severe coronary artery disease. A total of 53 patients (13 women) with severe coronary artery disease and preserved left ventricular ejection fraction were scheduled for coronary artery bypass grafting. Clinical assessment, anthropometric parameters, and quantification of fat depots were performed in all patients. The relative expression of the following genes were obtained in PVAT‑IMA, as well as epicardial, pericardial, and subcutaneous (SF) fat samples: angiotensinogen (AGT), angiotensin I converting enzyme 1 and 2 (ACE1and ACE2), glucagon‑like peptide receptors type 1 and 2 (GLP1R and GLP2R), phospholipid transfer protein (PLTP), adiponectin (ADIPOQ), omentin‑1 (ITLN1), and uncoupling protein 1 (UCP1). The expression of UCP1 (median [interquartile range [IQR], 2.5 [0.91-16.6]; P <0.01) and AGT(2.22 [0.65-6.2]; P <0.01) was higher in PVAT‑IMA compared with the SF depot. ADIPOQ expression was lower in pericardial and epicardial fat depots (median [IQR], 0.44 [0.23-2.3]; P <0.01). The expression of ITLN1 was increased in PVAT‑IMA as compared with epicardial and pericardial fat (P <0.001). PVAT‑IMA revealed differences in the expression of selected genes in relation to SF. We found a higher expression of ITLN1 in PVAT‑IMA compared with other adipose tissue depots, which could be associated with protective mechanisms against atherosclerosis in IMA. However, this remains a subject for further studies.

High blood pressure induced by vitamin D deficiency is associated with renal overexpression and hyperphosphorylation of Na+-K+-2Cl- cotransporter type 2.

Clinical and epidemiological studies have suggested a correlation between vitamin D deficiency (VDD) and high blood pressure (BP). This study aimed to test the hypothesis that high BP induced by VDD is associated with altered expression and covalent modification of apical sodium transporters along the nephron. The contributions of the intrarenal renin-angiotensin system (RAS) and oxidative stress were also investigated. Male Wistar rats were fed a vitamin D-free (n = 26) or standard diet (n = 25) for 30 days. BP was recorded using noninvasive and invasive procedures. The expression levels of total and phosphorylated apical sodium transporters in rat renal cortex and medulla were evaluated by immunoblotting. Intrarenal RAS components were assessed by immunoblotting and ELISA. Renal oxidative stress was analyzed by measuring the concentrations of thiobarbituric acid reactive substances and reduced glutathione. Higher BP levels in VDD rats than controls were accompanied by overexpression and hyperphosphorylation of renal cortical and medullary Na+-K+-2Cl- cotransporter type 2, enhanced levels of phosphorylated Na+/H+ exchanger type 3, and reduced expression levels of total and phosphorylated Na+/Cl- cotransporter. Changes in intrarenal RAS induced by VDD vs. controls included the marked elevation of medullary renin expression, higher expression of cortical angiotensinogen, higher urinary angiotensinogen excretion, and higher cortical and medullary angiotensin II content. VDD rats displayed higher thiobarbituric acid reactive substances/glutathione ratios in the renal cortex and medulla than controls. These results suggest that the molecular mechanisms underlying the effects of VDD on BP may include the upregulation of Na+-K+-2Cl- cotransporter type 2 and activation of intrarenal RAS and oxidative stress.

Abstract 15555: Potential Cure for Hypertension? The Effect of Crispr Genome Editing

Hypertension is recognized as one of the largest contributors to the global burden of disease. Unfortunately, for the majority of patients, hypertension is poorly controlled due, in part, to poor medical compliance resulting from the need to take one or more drugs, often several times daily. An ideal therapy would be administered a single time but yield long-term blood pressure control. Under the appropriate condition, we hypothesize that this modality could potentially lead to a cure for hypertension. In this study, we investigated whether that sustained, and possibly life-long, reductions in blood pressure could be achieved via Crispr-Cas9 mediated disruption of a key gene in the RAAS, Angiotensinogen (AGT). In vitro, we demonstrated that expression of Crispr-Cas9 system in the BRL 3A rat liver cell line led to a significant reduction in AGT protein levels (75% reduction, N=3, P&lt;0.01). Delivery of the Crispr-Cas9 system into the liver via systemic delivery of the hepatocyte-targeting AAV8 reduced both AGT mRNA (70% reduction, N=5, P&lt;0.01) and circulating AGT protein (50% reduction, N=5, P&lt;0.01) and Ang II levels (33% reduction, n=5, P&lt;0.01). In the SHR model of hypertension, Crispr-Cas9 mediated loss of AGT expression reduced systolic blood pressure in adult animals with established hypertension (30-35mmHg decrease in both females and males, N=12, P&lt;0.001). Importantly, AGT gene disruption also prevented the spontaneous development of hypertension in young pre-hypertensive SHR (SHR control: 55-60mmHg increase in systolic blood pressure both female and male SHR; SHR plus Crispr-Cas9: 30-33 mmHg increase. N=12. P&lt;0.001). Importantly, in all the models studied, reductions in blood pressure were sustained for at least 4 months. Importantly, the partial disruption of the hepatic AGT gene was sufficient to control hypertension but did not block the renin-angiotensin response to cardiovascular stress such as sodium depletion. In summary, we have demonstrated that targeting the Crispr-Cas9 system to RAAS reduces blood pressure and may be a potential therapy to achieve safe and sustained, possibly life-long, control of hypertension and this approach maybe a cure for hypertension.

MicroRNA-133a-Dependent Inhibition of Proximal Tubule Angiotensinogen by Renal TNF (Tumor Necrosis Factor).

We showed that intrarenal suppression of TNF (tumor necrosis factor) production under low salt (LS) conditions increases renal cortical AGT (angiotensinogen) mRNA and protein expression. Intrarenal injection of murine recombinant TNF attenuated increases of AGT in mice ingesting LS. Moreover, AGT mRNA and protein expression increased ≈6-fold and 2-fold, respectively, in mice ingesting LS that also received an intrarenal injection of a lentivirus construct that specifically silenced TNF in the kidney (U6-TNF-ex4). Silencing of TNF under normal salt and high salt (HS) conditions also resulted in increased AGT expression. Since renal TNF production decreases in response to LS and increases in response to HS, the data suggest that alterations in TNF production under these conditions modulate the degree of AGT expression. We also tested the hypothesis that TNF inhibits intrarenal AGT expression by a mechanism involving miR-133a. Expression of miR-133a decreased in mice given LS and increased in response to HS for 7 days. Intrarenal silencing of TNF reversed the effects of HS on miR-133a-dependent AGT expression. In contrast, intrarenal TNF administration increased miR-133a expression in the kidney. Collectively, the data suggest that miR-133a is a salt-sensitive microRNA that inhibits AGT in the kidney and is increased by TNF. The HS-induced increase in blood pressure observed following silencing of TNF was markedly reduced upon intrarenal administration of miR-133a suggesting that intrinsic effects of TNF in the kidney to limit the blood pressure response to HS include an increase in miR-133a, which suppresses AGT expression.

Abstract 286: Targeting Formyl Peptide Receptors as a Novel Approach to Treat Hypertension

Introduction: It is estimated that 15-30% of hypertensive patients are resistant to available drugs; and thus identifying novel therapeutic strategies is imperative. We have previously demonstrated that the formyl peptide receptor-1/2 (FPR) small-molecule agonist, Cmpd17b, exhibits anti-inflammatory and vasodilator actions. We investigated the efficacy of Cmpd17b to reduce hypertension and its associated end-organ damage. Methods: Hypertensive (BPH/2J) and normotensive (BPN/3J) mice underwent 24h conscious blood pressure recordings via telemetry from baseline until 4 weeks post Cmpd17b treatment (50 mg/kg/day, i.p.) or vehicle (8% tween80 in saline with 10% dimethyl sulfoxide, i.p.). The abdominal aorta dimension was assessed via ultrasound imaging at baseline and study end. Results: Hypertensive mice exhibited elevated mean arterial pressure compared to normotensive mice at baseline (Table). Cmpd17b reduced mean arterial pressure, left ventricle fibrosis, angiotensinogen expression and improved vascular distensibility. Conclusion: This study is the first to demonstrate that chronic FPR agonist administration reduces blood pressure in hypertensive mice, and further supports development of FPR-based therapies against hypertension-related organ damage.

Receptor-Associated Prorenin System in the Trabecular Meshwork of Patients with Primary Open-Angle Glaucoma and Neovascular Glaucoma.

The receptor-associated prorenin system (RAPS) is associated with several pathologic conditions, including diabetic retinopathy, age-related macular degeneration, and uveitis. Here, we show the involvement of RAPS in the trabecular meshwork (TM) from patients with primary open-angle glaucoma (POAG) and neovascular glaucoma (NVG) due to proliferative diabetic retinopathy. Anterior chamber (AC) levels of prorenin significantly increased in both POAG and NVG, as did those of angiotensin II in NVG alone, compared to cataract. In surgically excised TM tissues, (pro)renin receptor ((P)RR) and angiotensin II type 1 receptor (AT1R) co-localized with prorenin and angiotensinogen, respectively. In screening for various genes related to glaucoma, prorenin stimulation to human TM cells exclusively upregulated cell junction constituents connexin 43 and zona occludens 1, while downregulating an extracellular matrix-degrading enzyme tissue plasminogen activator, all of which were reversed by (P)RR blockade. In contrast, angiotensin II application upregulated a pro-angiogenic factor placental growth factor alone, which was abolished by AT1R blockade. Consistently, (P)RR and AT1R co-localized with these corresponding proteins in patient TM tissues. Oxidative stress, a known etiology for glaucoma, induced the expression of prorenin and angiotensinogen in human TM cells. These data suggest the contribution of RAPS to the molecular pathogenesis of POAG and NVG through TM tissue remodeling and AC angle angiogenesis.

STAT1 regulates interferon-γ-induced angiotensinogen and MCP-1 expression in a bidirectional manner in primary cultured mesangial cells.

Objective:Intrarenal interferon-γ significantly contributes to the development of glomerular injury in which angiotensinogen and monocyte chemoattractant protein 1 levels are elevated. However, the exact nature of the role that interferon-γ plays in regulating angiotensinogen and monocyte chemoattractant protein 1 expression has not been fully delineated. Therefore, the aim of this study was to investigate the role that interferon-γ plays in angiotensinogen and monocyte chemoattractant protein 1 expression.Methods:Primary cultured rat mesangial cells were treated with 0–20 ng/mL interferon-γ for 2, 8 or 24 hours. Expression levels of angiotensinogen, monocyte chemoattractant protein 1, suppressors of cytokine signaling 1, an intracellular suppressor of Janus kinase-signal transducers and activators of transcription signaling and activity of the Janus kinase-signal transducers and activators of transcription pathway were evaluated by reverse transcriptase polymerase chain reaction and western blot analysis.Results:Interferon-γ increased angiotensinogen expression in mesangial cells with maximal augmentation observed following 5 ng/mL interferon-γ at 8 hours of treatment (1.87 ± 0.05, mRNA, relative ratio). Further increases were reduced or absent using higher concentrations of interferon-γ. Following treatments, monocyte chemoattractant protein 1 expression was induced in a linear dose-dependent manner (6.85 ± 0.62-fold by 20 ng/mL interferon-γ at 24 hours). In addition, interferon-γ induced STAT1 phosphorylation and suppressors of cytokine signaling 1 expression in a linear dose-dependent manner. The suppression of STAT1 and suppressors of cytokine signaling 1 expression by small interference RNAs facilitated an increase in interferon-γ-induced angiotensinogen expression, indicating that these two factors negatively regulate angiotensinogen expression. In contrast, the increase in interferon-γ-induced monocyte chemoattractant protein 1 expression was attenuated in STAT1-deficient mesangial cells, suggesting that STAT1 positively regulates monocyte chemoattractant protein 1 expression in mesangial cells.Conclusion:These results demonstrate that while interferon-γ increases both angiotensinogen and monocyte chemoattractant protein 1 expression, STAT1 plays an opposing role in the regulation of each factor in mesangial cells.

Activation of the renin-angiotensin system in high fructose-induced metabolic syndrome.

High fructose intake induces hyperglycemia and hypertension. However, the mechanism by which fructose induces metabolic syndrome is largely unknown. We hypothesized that high fructose intake induces activation of the renin-angiotensin system (RAS), resulting in hypertension and metabolic syndrome. We provided 11-week-old Sprague–Dawley rats with drinking water, with or without 20% fructose, for two weeks. We measured serum renin, angiotensin II (Ang II), and aldosterone (Aldo) using ELISA kits. The expression of RAS genes was determined by quantitative reverse transcription polymerase chain reaction. High fructose intake increased body weight and water retention, regardless of food intake or urine volume. After two weeks, fructose intake induced glucose intolerance and hypertension. High fructose intake increased serum renin, Ang II, triglyceride, and cholesterol levels, but not Aldo levels. High fructose intake increased the expression of angiotensinogen in the liver; angiotensin-converting enzyme in the lungs; and renin, angiotensin II type 1a receptor (AT1aR), and angiotensin II type 1b receptor (AT1bR) in the kidneys. However, expression of AT1aR and AT1bR in the adrenal glands did not increase in rats given fructose. Taken together, these results indicate that high fructose intake induces activation of RAS, resulting in hypertension and metabolic syndrome.

P0752THE EXPRESSION AND DIAGNOSTIC VALUE OF URINE ANGIOTENSINOGEN IN CHRONIC KIDNEY DISEASE

Abstract Background and Aims This article aims to detect the expression of urine angiotensinogen (uAGT) in patients with chronic kidney disease (CKD) and its correlation with clinical and renal pathology. Method Patients who diagnosed with CKD and undergoing renal biopsy for the first visit to Sun Yat-sen Memorial Hospital from March 1st ,2018 to October 1st, 2019 were enrolled. First morning urine samples from CKD patients before renal biopsy and healthy volunteers as controls were collected during the same period. These samples were tested for uAGT by ELISA. Linear regression analysis was used to explore the correlation between uAGT and clinical indicators as well as renal pathology in CKD patients. The receiver operating curve (ROC curve) was used to explore the diagnostic value of uAGT for CKD stage 3 or above and glomerular sclerosis ratio&amp;gt;50%. Results A total of 133 CKD patients with 59 (44.4%) in stage 1, 31 (23.3%) in CKD stage 2, 17 (12.8%) in stage 3, 17 (12.8%) in stage 4 and 9 (6.7%) in stage 5 were included in our study. At the same time, 20 healthy volunteers were included as control. uAGT levels of CKD patients were significantly higher than healthy controls(275.0 vs 774.2,P&amp;lt;0.001). Compared with CKD stage 1-2 patients, uAGT levels in patients with stage CKD 3 or above were significantly increased, and the difference was statistically significant (P&amp;lt;0.001) (Table 1). The result of multivariate linear regression analysis showed that uAGT levels in CKD patients were positively correlated with 24h urine protein (beta = 0.193, P = 0.012) and negatively correlated with eGFR (beta = -0.489, P&amp;lt;0.001) (Table 2). We also demonstrated that uAGT was positively correlated with the ratio of glomerular sclerosis(P = 0.003) (Table 3). Our results showed that the area under the curve (AUC)of uAGT for the diagnosis of renal function with CKD stage 3 or above was 0.789 (Figure 1) with the cut-off value was1959.9pg/ml. The sensitivity and specificity were 51.2% and 97.3% respectively, Furthermore, the positive predictive value (PPV) was 88.0% and negative predictive value (NPV) was 82.95%.The AUC of uAGT for the diagnosis of renal pathological glomerular sclerosis ratio&amp;gt;50% was 0.677 (Figure 2).The cut-off value of uAGT was 2131.8pg/ml.The sensitivity and specificity were 50% and 89.5% respectively. Meanwhile, the PPV was 41.67% and the NPV was 92.25%. Conclusion uAGT was significantly increased in CKD patients, which is closely related with the urinary protein, eGFR, and renal pathology.The specific cut-off value of uAGT can be used as a predictive indicator of advanced CKD stage and severe glomerular sclerosis.

AJP-Regulatory, Integrative and Comparative Physiology: Looking Toward the Future

<i>AJP-Regulatory, Integrative and Comparative Physiology</i>: Looking Toward the Future

Angiotensin II Regulates Proliferation and Function of Stem Cells of Apical Papilla

IntroductionStem cells of apical papilla (SCAP) may be affected by inflammatory mediators released by activation with lipopolysaccharide (LPS) from infected pulpal cavities of necrotic immature teeth. Therefore, this study aimed to investigate the presence of a local renin-angiotensin system (RAS) and the role of angiotensin II (Ang II) on the modulation of SCAP in vitro. MethodsPrimary cultures of SCAP were incubated with LPS (0.1–10 μg/mL) for cell viability and quantification of the chemokine CCL2. Components of RAS were searched by gene expression of angiotensinogen (AGTN), angiotensin converting enzyme (ACE), renin, angiotensin receptor 1 (AT1) and 2 (AT2), and Mas receptor. Ang II was investigated in SCAP supernatants. Immunofluorescence was used to detect AGTN and AT1. Next, cells were treated with Ang II for viability/proliferation assessment, quantification of CCL2 and interleukin 6, and mineralization assay. Data were evaluated by analysis of variance using Tukey post hoc comparisons or the Student t test. P values <.05 were considered to be significant. ResultsLPS increased CCL2 production at 1 and 10 μg/mL. The gene expression of AGTN, renin, ACE, and AT1 was detected, but only ACE was increased by LPS. Ang II peptide was found in SCAP supernatants but unaltered by LPS. Both AGTN and AT1 proteins were detected by immunostaining. Ang II significantly induced SCAP proliferation, increased CCL2 production, down-regulated IL-6 release, and reduced the SCAP mineralization rate. ConclusionsA local RAS was found at the apical papilla, and Ang II was able to modulate SCAP function in vitro.