EC:3.4.24.B1 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.B1 (angiotensin-converting enzyme 2)
1,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The renin-angiotensin system is a far more complex enzymatic cascade than realized previously. Mounting evidence suggests sex-specific differences in the regulation of the renin-angiotensin system and arterial pressure. We examined the hemodynamic responses, angiotensin II receptor subtypes, and angiotensin-converting enzyme 2 gene expression levels after graded doses of angiotensin II in males and females. Mean arterial pressure was measured via telemetry in male and female rats in response to a 2-week infusion of vehicle, low-dose (50 ng/kg per minute SC) or high-dose (400 ng/kg per minute SC) angiotensin II. The effect of concurrent infusion of the angiotensin II type 2 receptor (AT(2)R) blocker (PD123319) was also examined. The arterial pressure response to high-dose angiotensin II was attenuated in females compared with males (24+/-8 mm Hg versus 42+/-5 mm Hg; P for the interaction between sex and treatment <0.002). Remarkably, low-dose angiotensin II decreased arterial pressure (11+/-4 mm Hg; P for the interaction between sex and treatment <0.02) at a dose that did not have an effect in males. This decrease in arterial pressure in females was abolished by AT(2)R blockade. Renal AT(2)R, angiotensin-converting enzyme 2, and left ventricular AT(2)R mRNA gene expressions were markedly greater in females than in males with a renal angiotensin II type 1a receptor:AT(2)R ratio of approximately 1 in females. Angiotensin II infusion did not affect renal AT(2)R mRNA expression but resulted in significantly less left ventricular mRNA expression. Renal angiotensin-converting enzyme 2 mRNA expression levels were greater in females than in males treated with high-dose angiotensin II (approximately 2.5 fold; P for the interaction between sex and treatment <0.05). In females, enhancement of the vasodilatory arm of the renin-angiotensin system, in particular, AT(2)R and angiotensin-converting enzyme 2 mRNA expression, may contribute to the sex-specific differences in response to renin-angiotensin system activation.
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PMID:Enhanced angiotensin II type 2 receptor mechanisms mediate decreases in arterial pressure attributable to chronic low-dose angiotensin II in female rats. 1893 41

Angiotensin-converting enzyme (ACE) and its homologue angiotensin-converting enzyme 2 (ACE2) are critical counter-regulatory enzymes of the renin-angiotensin system, and have been implicated in cardiac function, renal disease, diabetes, atherosclerosis and acute lung injury. Both ACE and ACE2 have catalytic activity that is chloride sensitive and is caused by the presence of the CL1 and CL2 chloride-binding sites in ACE and the CL1 site in ACE2. The chloride regulation of activity is also substrate dependent. Site-directed mutagenesis was employed to elucidate which of the CL1 and CL2 site residues are responsible for chloride sensitivity. The CL1 site residues Arg186, Trp279 and Arg489 of testicular ACE and the equivalent ACE2 residues Arg169, Trp271 and Lys481 were found to be critical to chloride sensitivity. Arg522 of testicular ACE was also confirmed to be vital to the chloride regulation mediated by the CL2 site. In addition, Arg514 of ACE2 was identified as a residue critical to substrate selectivity, with the R514Q mutant, relative to the wild-type, possessing a fourfold greater selectivity for the formation of the vasodilator angiotensin-(1-7) from the vasoconstrictor angiotensin II. The enhancement of angiotensin II cleavage by R514Q ACE2 was a result of a 2.5-fold increase in V(max) compared with the wild-type. Inhibition of ACE2 was also found to be chloride sensitive, as for testicular ACE, with residues Arg169 and Arg514 of ACE2 identified as influencing the potency of the ACE2-specific inhibitor MLN-4760. Consequently, important insights into the chloride sensitivity, substrate selectivity and inhibition of testicular ACE and ACE2 were elucidated.
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PMID:Residues affecting the chloride regulation and substrate selectivity of the angiotensin-converting enzymes (ACE and ACE2) identified by site-directed mutagenesis. 1902 74

Angiotensin II (ANG II), the biologically active peptide of the renin-angiotensin system (RAS), is generated by angiotensin-converting enzyme (ACE) and is a regulator of cardiovascular homeostasis. Recently, there has been increasing evidence that ANG II is involved in the regulation of cell proliferation and migration, as well as angiogenesis via the ANG II-type 1 receptor (AT1R). These findings suggest that the ACE-ANG II-AT1R pathway is related to cancer biology. Previous reports have shown that ACE is preferentially expressed in pancreatic ductal adenocarcinoma (PDAC) tissues. Recently a homologue of ACE, angiotensin-converting enzyme 2 (ACE2), was reported to counterbalance the function of ACE, but the expression and role of ACE2 in PDAC are still unclear. In the present study, we analyzed the expression of ACE2 in invasive human PDAC and surrounding non-malignant tissues by Western blot analysis and immunohistochemistry. The ANG II concentration in homogenates of pancreatic tissues was measured with ELISA, and ACE2 protein was detected by Western blot analysis in BxPC3 and SW1990 human pancreatic ductal cancer cells. We have shown for the first time that the expression of ACE2 is decreased in PDAC tissues, in which ANG II was accumulated. Treatment of BxPC3 and SW1990 cells with ANG II decreased the expression of ACE2. Therefore, ANG II may contribute to the down-regulation of ACE2. Moreover, reduction of ACE2 expression by RNA interference promoted the proliferation of cultured pancreatic cancer cells. These findings suggest that ACE2 may have clinical potential as a novel molecular target for the treatment of PDAC.
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PMID:Decreased expression of angiotensin-converting enzyme 2 in pancreatic ductal adenocarcinoma is associated with tumor progression. 1921 5

The present work introduces a brief review of the actual knowledge concerning the enzymes involved in the biosynthesis of the active angiotensins, followed by a presentation of their main physio-pharmacological actions. The enzymatic pathways that generate active ang. II (1-8) are complemented with data concerning its transformation into angiotensin III (2-8), ang. IV (3-8), ang. V (1-5) and ang. 1-7. Besides the classic renin of renal origin, the tissue isorenins, represented by tonin and cathepsins D and G, inactive angiotensin-I-forming are also reviewed. Furthermore, chymase and the new angiotensin-converting enzyme 2 (ACE2), which generates angiotensin 1-7, having opposite properties from the mother-substance (Ang. II) are discussed at length. The presentation of properties of angiotensin-generating enzymes is followed by the presentation of the action of angiotensinases (aminopetidases, carboxypeptidase and endopeptidases), which are involved both in the generation of biologically active angiotensin peptides and in their inactivation.
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PMID:Biosynthesis and physio-pharmacological actions of angiotensin peptides: 1. Synthetic enzymes. 1929 99

Recent studies have established a new regulatory axis in the renin-angiotensin system (RAS). In this axis, angiotensin (Ang)-(1-7) is finally produced from Ang I or Ang II by the catalytic activity of angiotensin-converting enzyme 2 (ACE2). Ang-(1-7) shows actions different from those of AT(1) receptor stimulation, such as vasodilatation, natriuresis, anti-proliferation and an increase in the bradykinin-NO (nitric oxide) system. As the catalytic efficiency of ACE2 is approximately 400-fold higher with Ang II as a substrate than with Ang I, this axis is possibly acting as a counter-regulatory system against the ACE/Ang II/AT(1) receptor axis. The signaling pathway of the ACE2-Ang-(1-7) axis has not yet been totally and clearly understood. However, a recent report suggests that the Mas oncogene acts as a receptor for Ang-(1-7). Intracellular signaling through Mas is not clear yet. Several factors such as Akt phosphorylation, protein kinase C activation and mitogen-activated protein (MAP) kinase inhibition seem to be involved in this signaling pathway. Further investigations are needed to clarify the regulation and mechanism of action of ACE2 and Ang-(1-7). However, this second axis through ACE2 and Ang-(1-7) in RAS can be an important target for the therapy of cardiovascular and metabolic disorders.
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PMID:Devil and angel in the renin-angiotensin system: ACE-angiotensin II-AT1 receptor axis vs. ACE2-angiotensin-(1-7)-Mas receptor axis. 1946 48

In spite of recent advancements in the treatment of pulmonary hypertension, successful control has yet to be accomplished. The abundant presence of angiotensin-converting enzyme 2 (ACE2) in the lungs and its impressive effect in the prevention of acute lung injury led us to test the hypothesis that pulmonary overexpression of this enzyme could produce beneficial outcomes against pulmonary hypertension. Monocrotaline (MCT) treatment of mice for 8 weeks resulted in significant increases in right ventricular systolic pressure, right ventricle:left ventricle plus septal weight ratio, and muscularization of pulmonary vessels. Administration of a lentiviral vector containing ACE2, 7 days before MCT treatment prevented the increases in right ventricular systolic pressure (control: 25+/-1 mm Hg; MCT: 44+/-5 mm Hg; MCT+ACE2: 26+/-1 mm Hg; n=6; P<0.05) and right ventricle:left ventricle plus septal weight ratio (control: 0.25+/-0.01; MCT: 0.31+/-0.01; MCT+ACE2: 0.26+/-0.01; n=8; P<0.05). A significant attenuation in muscularization of pulmonary vessels induced by MCT was also observed in animals overexpressing ACE2. These beneficial effects were associated with an increase in the angiotensin II type 2 receptor:angiotensin II type 1 receptor mRNA ratio. Also, pulmonary hypertension-induced increases in proinflammatory cytokines were significantly attenuated by lentiviral vector-containing ACE2 treatment. Furthermore, ACE2 gene transfer in mice after 6 weeks of MCT treatment resulted in a significant reversal of right ventricular systolic pressure. These observations demonstrate that ACE2 overexpression prevents and reverses right ventricular systolic pressure and associated pathophysiology in MCT-induced pulmonary hypertension by a mechanism involving a shift from the vasoconstrictive, proliferative, and fibrotic axes to the vasoprotective axis of the renin-angiotensin system and inhibition of proinflammatory cytokines.
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PMID:Prevention of pulmonary hypertension by Angiotensin-converting enzyme 2 gene transfer. 1956 52

Angiotensin-(1-7) (Ang-[1-7]) is a heptapeptide member of the renin-angiotensin system (RAS), and acts as a vasodilator and antagonist of angiotensin II (Ang II) in the vasculature. The role of Ang-(1-7) in regulating kidney function is not well understood. Within the kidneys, Ang-(1-7) is generated by angiotensin-converting enzyme 2 (ACE2)-mediated degradation of Ang II, sequential cleavage of the precursor angiotensin I (Ang I) by ACE2 and ACE, or the actions of brush-border membrane peptidases on Ang I. Ang-(1-7) mediates its effects via binding to kidney Mas receptors, although some actions may occur via Ang II AT1 or AT2 receptors. In vitro studies suggest that Ang-(1-7) is an intrarenal vasodilator. Ang-(1-7) has been reported to induce either natriuresis/diuresis or sodium and water retention, via modulation of sodium transporters in the proximal tubule and loop of Henle, and collecting duct water transport. In the proximal tubule, Ang-(1-7) antagonizes growth-promoting signaling pathways via activation of a protein tyrosine phosphatase, whereas in mesangial cells, Ang-(1-7) stimulates cell growth via activation of mitogen-activated protein kinases. The phenotype of the Mas gene knockout mouse suggests that Ang-(1-7)-signaling events exert cardiovascular protection by regulating blood pressure, and by limiting production of reactive oxygen species and extracellular matrix proteins. Ang-(1-7) also protects against renal injury in the renal wrap hypertension model, independent of effects on blood pressure. In diabetic nephropathy, however, the role of Ang-(1-7) on disease progression remains unclear. In summary, Ang-(1-7) and its receptor Mas have emerged as important components of the intrarenal RAS. The signaling and downstream effects of Ang-(1-7) in the kidney are complex and appear to be cell specific. The body of evidence suggests that Ang-(1-7) is protective against endothelial dysfunction or Ang II-stimulated proximal tubular injury, although the overall effects on glomerular function require further study.
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PMID:Angiotensin-(1-7) and its effects in the kidney. 1957 9

Alterations within the RAS (renin-angiotensin system) are pivotal for the development of renal disease. ACE2 (angiotensin-converting enzyme 2) is expressed in the kidney and converts the vasoconstrictor AngII (angiotensin II) into Ang-(1-7), a peptide with vasodilatory and anti-fibrotic actions. Although the expression of ACE2 in the diabetic kidney has been well studied, little is known about its expression in non-diabetic renal disease. In the present study, we assessed ACE2 in rats with acute kidney injury induced by STNx (subtotal nephrectomy). STNx and Control rats received vehicle or ramipril (1 mg. kg (-1) of body weight . day (-1), and renal ACE, ACE2 and mas receptor gene and protein expression were measured 10 days later. STNx rats were characterized by polyuria, proteinuria, hypertension and elevated plasma ACE2 activity (all P<0.01) and plasma Ang-(1-7) (P<0.05) compared with Control rats. There was increased cortical ACE binding and medullary mas receptor expression (P<0.05), but reduced cortical and medullary ACE2 activity in the remnant kidney (P<0.05 and P<0.001 respectively) compared with Control rats. In STNx rats, ramipril reduced blood pressure (P<0.01), polyuria (P<0.05)and plasma ACE2 (P<0.01), increased plasma Ang-(1-7) (P<0.001), and inhibited renal ACE(P<0.001). Ramipril increased both cortical and medullary ACE2 activity (P<0.01), but reduced medullary mas receptor expression (P<0.05). In conclusion, our results show that ACE2 activity is reduced in kidney injury and that ACE inhibition produced beneficial effects in association with increased renal ACE2 activity. As ACE2 both degrades AngII and generates the vasodilator Ang-(1-7), a decrease in renal ACE2 activity, as observed in the present study, has the potential to contribute to the progression of kidney disease.
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PMID:Reduction in renal ACE2 expression in subtotal nephrectomy in rats is ameliorated with ACE inhibition. 1969 82

We have previously shown the presence of immunoreactive angiotensin-(1-7) [Ang-(1-7)] in rat ovary homogenate and its stimulatory effect on estradiol and progesterone production in vitro. In the current study, we investigated the presence and cellular distribution of Ang-(1-7) and the Mas receptor, the expression of Mas and angiotensin-converting enzyme 2 (ACE2) messenger RNA (mRNA), and the enzymatic activity in the rat ovary following gonadotropin stimulation in vivo. Immature female Wistar rats (25 days old) were injected subcutaneously (SC) with equine chorionic gonadotropin (eCG, 20 IU in 0.2 mL) or vehicle 48 hours before euthanasia. Tissue distributions of Ang-(1-7), Mas receptor, and ACE2 were evaluated by immunohistochemistry, along with angiotensin II (Ang II) localization, while the mRNA expression levels of Mas receptor and ACE2 were evaluated by real-time polymerase chain reaction (PCR). In addition, we determined the activity of neutral endopeptidase (NEP), prolyl endopeptidase (PEP), and ACE by fluorometric assays. After eCG treatment, we found strong immunoreactivity for Ang-(1-7) and Mas primarily in the theca-interstitial cells, while Ang II appeared in the granulosa but not in the thecal layer. Equine chorionic gonadotropin treatment increased Mas and ACE2 mRNA expression compared with control animals (3.3- and 2.1-fold increase, respectively; P < .05). Angiotensin-converting enzyme and NEP activities were lower, while PEP activity was higher in the eCG-treated rats (P < .05). These data show gonadotropin-induced changes in the ovarian expression of Ang-(1-7), Mas receptor, and ACE2. These findings suggest that the renin-angiotensin system (RAS) branch formed by ACE2/Ang-(1-7)/Mas, fully expressed in the rat ovary and regulated by gonadotropic hormones, could play a role in the ovarian physiology.
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PMID:Gonadotropin stimulation increases the expression of angiotensin-(1--7) and MAS receptor in the rat ovary. 1970 90

In general, treatment with most angiotensin receptor blockers (ARBs) increases plasma angiotensin II (Ang II) level because of a lack of negative feedback on renin activity. Olmesartan is a potential ARB inducing activation of angiotensin-converting enzyme 2 (ACE2) that hydrolyzes Ang II to Ang 1-7, and has shown a beneficial effect on ventricular remodeling. Indeed, a previous study reported that olmesartan treatment resulted in decreased plasma levels of Ang II and aldosterone. However, there has not yet been a study showing the relationship of chronic effects of olmesartan on Ang II and the left ventricular mass index (LVMI) in comparison with those of other ARB.A total of 50 stable outpatients with essential hypertension who had received candesartan for more than 1 year were randomized into two groups: control group (n=25): continuous candesartan treatment at a stable dose; and olmesartan group (n=25): candesartan (8 mg day(-1)) was changed to olmesartan given at a dose of 20 mg day(-1). There was no difference in the baseline characteristics between the two groups. In the control group, there were no significant changes in blood pressure, LVMI or biomarkers during 12 months of study. In the olmesartan group, blood pressure did not change and plasma levels of Ang II decreased during 12 months of study, whereas LVMI was significantly decreased after 12 months (135+/-36 vs. 123+/-29 g m(-2); P<0.01).These findings indicate that replacing candesartan with olmesartan decreased LVMI in association with a sustained decrease of plasma Ang II over a 12-month period without changing blood pressure or plasma aldosterone in patients with essential hypertension.
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PMID:Comparison of the long-term effects of candesartan and olmesartan on plasma angiotensin II and left ventricular mass index in patients with hypertension. 1994 30

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