Expression Levels Of Angiotensinogen Research Articles

Intrarenal renin–angiotensin system activation and macrophage infiltrations in pediatric chronic glomerulonephritis

BackgroundThe current study tested the hypothesis that urinary angiotensinogen (UAGT) and urinary monocyte chemoattractant protein-1 (UMCP-1) levels provide a specific index of intrarenal renin–angiotensin system (RAS) status and the degree of infiltration of macrophages associated with RAS blockade and immunosuppressant treatment in pediatric patients with chronic glomerulonephritis.MethodsWe measured baseline UAGT and UMCP-1 levels to examine the correlation between glomerular injury in 48 pediatric chronic glomerulonephritis patients before treatment. Furthermore, we performed immunohistochemical analysis of angiotensinogen (AGT) and CD68 in 27 pediatric chronic glomerulonephritis patients treated with RAS blockades and immunosuppressants for 2 years. Finally, we examined the effects of angiotensin II (Ang II) on monocyte chemoattractant protein-1 (MCP-1) expression in cultured human mesangial cells (MCs).ResultsBaseline UAGT and UMCP-1 levels positively correlated with urinary protein levels, scores for mesangial hypercellularity, rate of crescentic formation, and expression levels of AGT and CD68 in renal tissues (p < 0.05). UAGT and UMCP-1 levels were significantly decreased after RAS blockade and immunosuppressant treatment (p < 0.01), which was accompanied by AGT and CD68 (p < 0.01), as well as the magnitude of glomerular injury. Cultured human MCs showed increased MCP-1 messenger ribonucleic acid and protein levels after Ang II treatment (p < 0.01).ConclusionsThe data indicates that UAGT and UMCP-1 are useful biomarkers of the degree of glomerular injury during RAS blockade and immunosuppressant treatment in pediatric patients with chronic glomerulonephritis.

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.

Tanshinone IIA contributes to the pathogenesis of endometriosis via renin angiotensin system by regulating the dorsal root ganglion axon sprouting

AimsOur study was designed to explore the function and mechanism of Tanshinone IIA in alleviating pain syndrome caused by endometriosis (EMs). Main methodsFemale Sprague-Dawley rats went through autotransplantation operation to establish EMs model. The rats were randomly divided into five groups: sham, model, positive, Tanshinone IIA (L) (3 mg/kg/d) and Tanshinone IIA (H) (12 mg/kg/d) group. Volume of ectopic endometrium was measured after 21 days of continuous administration. Serum estradiol (E2) was detected by enzyme linked immunosorbent assay (Elisa). The protein expression of angiotensinogen (AGT), renin (REN), angiotensin converting enzyme (ACE), angiotensin II (ANGII) and angiotensin II type 2 receptor (AT2) in the dorsal root ganglion (DRG) neurons were measured by immunohistochemistry and Western Blotting. The mRNA expression levels of AGT and ANGII were measured by Real-time polymerase chain reaction (PCR). Key findingsTissue measurements showed that tanshinone IIA significantly inhibited the growth of ectopic endometrium. Tanshinone IIA could improve the paw withdrawal threshold thus reducing the mechanical hyperalgesia of EMs rats. Moreover, Tanshinone IIA regulated the DRG renin angiotensin system (RAS) by reducing the protein expression of AGT, REN, ACE, ANGII and AT2 in DRG neurons. Furthermore, Real-time PCR results also showed that the mRNA expression levels of AGT and ANGII in the DRG neurons were decreased. SignificanceThe Tanshinone IIA inhibitory effect on the EMs associated pain in EMs rats might occur through decreasing the expression of E2, ANGII and AT2, thus halting DRG sprouting and promoting hyperalgesia threshold.

Effects of Ginkgo biloba leaf extract on local renin-angiotensin system through TLR4/NF-κB pathway in cardiac myocyte.

The present study investigated the effects of Ginkgo biloba leaf extract (GBE50) on lipopolysaccharide (LPS) induced Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway and its effects on angiotensinogen (ATG) and AT1a receptor, so as to explore the mechanism of GBE50 in prevention and treatment of left ventricular remodeling. In vitro cultured neonatal rat ventricular myocytes (NRVMs) were divided into 4 groups including i) control group: DMEM medium; ii) LPS group: iii) LPS + GBE50 group; iv) LPS + caffeic acid phenethyl ester (CAPE, specific inhibitor of NF-κB) group. Nuclear translocation of NF-κB p65 was detected by immunocytochemical method after intervention for 24 h. Expression of TLR4, ATG, AT1a receptors and β-myosin heavy chain (β-MHC) mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR). Protein content of cardiomyocytes was measured by Coomassie Brilliant Blue method. Under LPS stimulation, expression level of TLR4 mRNA in NRVMs was significantly increased (P<0.01), nuclear translocation of NF-κB p65 was increased, expression levels of ATG, AT1a receptor and β-MHC mRNA and the protein content in cells were also increased significantly (P<0.01). GBE50 and CAPE significantly inhibited nuclear translocation of NF-κB p65. GBE50 and CAPE treatments also reduced the increased mRNA levels of TLR4, ATG, AT1a receptor and β-MHC and protein content in cell caused by LPS stimulation. We concluded that, GBE50 can inhibit the activation of local renin-angiotensin system by inhibiting the activation of TLR4/NF-κB and TLR4/NF-κB, signaling pathway inhibition may be one of the mechanisms of the role of Ginkgo biloba leaf extract in preventing myocardial remodeling.

Angiotensin II induces an increase in MMP-2 expression in idiopathic ascending aortic aneurysm via AT1 receptor and JNK pathway.

The cellular and molecular mechanisms responsible for human idiopathic ascending aortic aneurysm (IAAA) remain unknown. Matrix metalloproteinase-2 (MMP-2) is a key enzyme for the degradation of extracellular matrix in aneurysmal walls. The aim of this study was to elucidate the role of the angiotensin II (Ang II) pathway in MMP-2 induction in IAAA aortic walls. Quantitative polymerase chain reaction and western blot analysis were used to compare the MMP-2 mRNA and protein levels in ascending aortic specimens with those in IAAA patients (n = 10) and heart transplant donors (n = 5) without any aortopathy. It was found that MMP-2 expression was significantly increased, which was associated with elastic lamellae disruption in IAAA walls. Additionally, the expression levels of angiotensinogen (AGT) and Ang II in the ascending aortic tissues from individuals with and without IAAAs were detected by western blot analysis and radioimmunoassay, respectively. The results demonstrated that the expressions of AGT and Ang II protein were significantly increased in the ascending aortic tissues of IAAA patients. Furthermore, whether Ang II induces MMP-2 expression was investigated using human IAAA walls ex vivo culture. It was found that exogenous Ang II increased the MMP-2 expression in a dose-dependent manner, which was completely inhibited by the Ang II type 1 receptor (AT1R) inhibitor candesartan and was mediated by c-Jun N-terminal kinase (JNK) activation. Taken together, these results indicate that Ang II can induce an increase of MMP-2 expression via AT1R and JNK in ex vivo cultured IAAA aortic walls, and suggest that angiotensin receptor blocker (ARB) drugs and JNK inhibitors have the potential in the prevention or treatment of IAAAs.

Changes in urinary angiotensinogen posttreatment in pediatric IgA nephropathy patients.

Recently, we demonstrated that urinary angiotensinogen (AGT) levels are increased and reflect intrarenal renin-angiotensin system (RAS) status in pediatric patients with chronic glomerulonephritis. Therefore, this study was performed to test the hypothesis that urinary AGT (UAGT) levels provide a specific index of intrarenal RAS status associated with RAS blockade treatment in pediatric IgA nephropathy (IgAN) patients. We measured plasma and UAGT levels and urinary transforming growth factor beta (TGF-β) levels, after which we performed immunohistochemical analysis of AGT, angiotensin II (Ang II), and TGF-β in 24 pediatric IgAN patients treated with RAS blockades for 2 years. Paired tests were used to analyze the changes from baseline to study end. Although there was no change in plasma AGT levels, UAGT and TGF-β levels were significantly decreased after RAS blockade, which was accompanied by the expression levels of AGT, Ang II, and TGF-β, as well as the magnitude of glomerular injury. Baseline UAGT levels positively correlated with diastolic blood pressure, urinary protein levels, scores for mesangial hypercellularity, and the expression levels of AGT, Ang II, and TGF-β in renal tissues. These data indicate that UAGT is a useful biomarker of intrarenal RAS activation, which is associated with glomerular injury during RAS blockade in pediatric IgAN patients.

Epigenetic control of angiotensinogen and CYP11B2 gene expression in the hypertrophic hearts

Purpose: The activation of local Renin-Angiotensin-Aldosterone System (RAAS) plays a pivotal role in the overall pathophysiology of the cardiovascular diseases. We have reported increased mRNA levels of angiotensinogen and CYP11B2 (aldosterone synthase gene) in the experimental hypertensive hearts. The mechanism of control of gene expression of each component of RAAS gene in the human hearts is unknown. We analyzed epigenetic alteration, which controls the gene of angiotensinogen and CYP11B2 in the human hypertrophic hearts. Methods: Nine cardiomyopathic hearts which were diagnosed by echo cardiography and MRI and six controls (non-cardiomyopathy) were analyzed. The mRNA expression levels of angiotensinogen and CYP11B2 were measured by real time PCR. The methylation status of the prompter region of angiotensinogen and CYP11B2 gene were measured using Bisulfite sequencing as reported elsewhere. Results: CpG dinucleotides in the CYP11B2 promoter were found to be hypermethylated in tissues with low expression, but not in those with high expression, of CYP11B2. CYP11B2 mRNA levels were inversely correlated with CYP11B2 methylation in human myocardium, and increased CYP11B2 mRNA levels were associated with CYP11B2 demethylation in the hypertrophic heart. CpG dinucleotides in the angiotensinogen gene promoter were also found to be hypermethylated in tissues with low expression. However, no correlation between angiotenisnogen mRNA levels and methylation was found in the hypertrophic hearts. Conclusions: Advances in understanding of epigenetic modifications of tissue RAAS in the progression of cardiac hypertrophy and heart failure could be of great significance in predicting the pace of disease progression, developing targeted therapeutic strategies in preventing the progression of cardiovascular diseases.

GW24-e0025 Endothelial blockade induced RAAS expression up-regulation and blood pressure regulation

ObjectivesTo compare the level of expression of the renin-angiotensin-aldosterone system (RAAS) in mice with or without the endothelin-1 receptor antagonist bosentan and to examine the potential value in blood pressure...

GW24-e0020 The effect of dual blockade of RAAS and endothelin system in blood pression control

ObjectivesTo compare the level of expression of the renin-angiotensin-aldosterone system (RAAS) in mice with or without the endothelin-1 receptor antagonist bosentan and to examine the potential value in blood pressure...

Advanced glycation end-products activate the renin-angiotensin system through the RAGE/PI3-K signaling pathway in podocytes

The purpose of this study was to investigate the effects of advanced glycation end-products (AGEs) on the components of the renin-angiotensin system (RAS) in podocytes and to understand the mechanism of these effects. Immortalized mouse podocytes were exposed to various concentrations of AGEs for different time intervals. The expression levels of angiotensinogen (AGT), angiotensin II type 1 and 2 receptors (AT1R and AT2R) and renin were examined by real-time PCR and western blot; the receptor for AGEs (RAGE) and both Akt and phosphorylated Akt were examined by western blot; levels of angiotensin II (Ang II) were assayed by ELISA, and the activity of angiotensin-converting enzyme (ACE) was evaluated by measuring the production of hippuric acid in vitro. Treatment with AGEs resulted in significant increases in the expression of AGT (62%, P=0.002) and AT1R (59%, P=0.01). Moreover, Ang II levels increased significantly in both cell lysates (70%, P=0.018) and conditioned media (65%, P=0.01). ACE activity was also significantly higher in cell lysates (68% , P= 0.035) and conditioned media (65%, P=0.023). There were no changes in renin or AT2R expression (P > 0.05). AGEs did increase the expression of RAGE by 50% (P=0.012) and the phosphorylation of Akt by 100% (P=0.001). When podocytes were pretreated with anti-RAGE antibody (50 µg/ml) or the phosphoinositide 3-kinase (PI3-K) inhibitor, LY294002 (10 µM), the AGEs-induced increases in AGT and AT1R expression were reduced. Likewise, Ang II levels and ACE activity decreased significantly. AGEs activate the RAS in podocytes through the RAGE-PI3-K/Akt-dependent pathway and lead to an increase in podocyte apoptosis.

DUAL BLOCKADE OF RAAS & ET SYSTEM IN BLOOD PRESSURE REGULATION

ObjectivesTo compare the level of expression of the renin-angiotensin-aldosterone system (RAAS) in mice with or without the endothelin-1 receptor antagonist bosentan and to examine the potential value in blood pressure...

Endothelin-1 receptor blockade induces upregulation of renin-angiotensin-aldosterone system expression in terms of blood pressure regulation

To compare the level of expression of the renin-angiotensin-aldosterone system (RAAS) in mice with or without the endothelin-1 receptor antagonist bosentan and to examine the potential value in blood pressure regulation. Bosentan (10 mg/kg/d) and placebo were given to two groups of male C57BL/6 mice (n=5) from ages 6 to 12 weeks. The mRNAs of liver, kidney and lung were isolated for Northern blot analysis. A further 15 male C57BL/6 mice were divided into three groups (n=5): mice in group A were given the angiotensin II type 1 receptor blocker valsartan (10 mg/kg/d); mice in group B were given bosentan (10 mg/kg/d); and mice in group C were given both valsartan and bosentan (10 mg/ kg/d for each drug). All mice were administered the drugs from 6 to 12 weeks of age and had their systolic blood pressure (SBP) measured at the end of the drug treatments. Northern blot analysis demonstrated that the expression levels of angiotensinogen in liver (p=0.0126), renin in kidney (p=0.002), and angiotensin-converting enzyme in lung (p=0.0041) were upregulated in mice treated with bosentan. No difference in SBP was found among the groups before drug administration. Six weeks after monotherapy with valsartan, SBP was slightly lowered (126+/-2 vs. 122+/-3 mmHg, p=0.0381). Monotherapy with bosentan also had a small effect on SBP (126+/-2 vs. 122+/-3 mmHg, p=0.0381), whereas dual blockade with valsartan and bosentan significantly lowered SBP (127+/-3 vs. 103+/-3 mmHg, p<0.001). We conclude that RAAS components are upregulated under endothelin blockade. Dual blockade of the RAAS and endothelin system is beneficial for blood pressure control.