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Molecular Biology Reports May 2021Angiotensin-converting enzyme (ACE, EC 3.4.15.1) in the renin-angiotensin system regulates blood pressure by catalyzing angiotensin I to the vasoconstrictor angiotensin...
Angiotensin-converting enzyme (ACE, EC 3.4.15.1) in the renin-angiotensin system regulates blood pressure by catalyzing angiotensin I to the vasoconstrictor angiotensin II. In this study, the ACE was purified and characterized from sheep lung. The kinetic properties of the ACE were designated. The inhibition effect of captopril, a specific ACE inhibitor, was determined. ACE was purified from sheep lung using the affinity chromatography method in one step. NHS-activated Sepharose 4 Fast Flow as column filler and lisinopril as a ligand in this method used. The molecular weight and purity of ACE were designated using the SDS-PAGE method. Optimum temperature and optimum pH were found for purified ACE. K and V values from Lineweaver-Burk charts determined. The inhibition type, IC, and K values of captopril on purified ACE were identified. ACE was 6405-fold purified from sheep lung by affinity chromatography in one step and specific activity was 16871 EU/mg protein. The purity and molecular weight of ACE were found with SDS-PAGE and observed two bands at around 60 kDa and 70 kDa on the gel. Optimum temperature and optimum pH were designated for purified ACE. Optimum temperature and pH were found as 40 °C and pH 7.4, respectively. V and K values were calculated to be 35.59 (µmol/min).mL and 0.18 mM, respectively. IC value of captopril was found as 0.51 nM. The inhibition type of captopril was determined as non-competitive from the Lineweaver-Burk graph and the K value was 0.39 nM. As a result, it was observed in this study that the ACE enzyme can be successfully purified from sheep lungs in one step. Also, it was determined that captopril, which is a specific ACE inhibitor, has a significant inhibitory effect with a very low IC value of 0.51 nM.
Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Captopril; Chromatography, Affinity; Electrophoresis, Polyacrylamide Gel; Hydrogen-Ion Concentration; Inhibitory Concentration 50; Kinetics; Lisinopril; Lung; Molecular Weight; Peptidyl-Dipeptidase A; Sheep; Temperature
PubMed: 34086160
DOI: 10.1007/s11033-021-06432-8 -
Biochemical Pharmacology Feb 2023Cardiovascular disease is the major cause of mortality and disability, with hypertension being the most prevalent risk factor. Excessive activation of the... (Review)
Review
Cardiovascular disease is the major cause of mortality and disability, with hypertension being the most prevalent risk factor. Excessive activation of the renin-angiotensin system (RAS) under pathological conditions, leading to vascular remodeling and inflammation, is closely related to cardiovascular dysfunction. The counter-regulatory axis of the RAS consists of angiotensin-converting enzyme 2 (ACE2), angiotensin (1-7), angiotensin (1-9), alamandine, proto-oncogene Mas receptor, angiotensin II type-2 receptor and Mas-related G protein-coupled receptor member D. Each of these components has been shown to counteract the effects of the overactivated RAS. In this review, we summarize the latest insights into the complexity and interplay of the counter-regulatory RAS axis in hypertension, highlight the pathophysiological functions of ACE2, a multifunctional molecule linking hypertension and COVID-19, and discuss the function and therapeutic potential of targeting this counter-regulatory RAS axis to prevent and treat hypertension in the context of the current COVID-19 pandemic.
Topics: Humans; Angiotensin I; Angiotensin-Converting Enzyme 2; COVID-19; Hypertension; Pandemics; Peptide Fragments; Receptors, G-Protein-Coupled; Renin-Angiotensin System
PubMed: 36481346
DOI: 10.1016/j.bcp.2022.115370 -
Endocrine May 2021To study the receptor for Angiotensin (Ang) 1-7 using a radioligand (I-Ang 1-7)-binding assay. For more than a decade, Mas has been viewed as the receptor for Ang 1-7;...
PURPOSE
To study the receptor for Angiotensin (Ang) 1-7 using a radioligand (I-Ang 1-7)-binding assay. For more than a decade, Mas has been viewed as the receptor for Ang 1-7; however, Ang 1-7 binding has not been pharmacologically characterized in tissue membrane preparations.
METHODS
Radioligand-binding assays were carried out using tissue membrane preparations using radioiodinated Angiotensin 1-7 (I-Ang 1-7) to characterize its binding site. Non-radioactive I-Ang 1-7 was used to test if the addition of an iodine to the tyrosine moiety of Ang 1-7 changes the ability of Ang 1-7 to competitively inhibit I-Ang 1-7 binding.
RESULTS
I-Ang 1-7 binds saturably, with moderately high affinity (10-20 nM) to a binding site in rat liver membranes that is displaceable by I-Ang 1-7 at nanomolar concentrations (IC = 62 nM) while Ang 1-7 displaces at micromolar concentrations (IC = 80 µM) at ~22 °C. This binding was also displaceable by inhibitors of metalloproteases at room temperature. This suggests that I-Ang 1-7 binds to MMPs and/or ADAMs as well as other liver membrane elements at ~ 22 °C. However, when I-Ang 1-7-binding assays were run at 0-4 °C, the same MMP inhibitors did not effectively compete for I-Ang 1-7.
CONCLUSIONS
The addition of an iodine molecule to the tyrosine in position 4 of Ang 1-7 drastically changes the binding characteristics of this peptide making it unsuitable for characterization of Ang 1-7 receptors.
Topics: Angiotensin I; Angiotensin II; Animals; Iodine Radioisotopes; Peptide Fragments; Rats; Receptors, Angiotensin
PubMed: 33415576
DOI: 10.1007/s12020-020-02572-2 -
Molecular and Cellular Endocrinology Jun 2021The identification of an alternate extended form of angiotensin I composed of the first twelve amino acids at the N-terminal of angiotensinogen has generated new... (Review)
Review
The identification of an alternate extended form of angiotensin I composed of the first twelve amino acids at the N-terminal of angiotensinogen has generated new knowledge of the importance of noncanonical mechanisms for renin independent generation of angiotensins. The human sequence of the dodecapeptide angiotensin-(1-12) [N-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Va-Ile-COOH] is an endogenous substrate that in the rat has been documented to be present in multiple organs including the heart, brain, kidney, gut, adrenal gland, and the bone marrow. Newer studies have confirmed the existence of Ang-(1-12) as an Ang II-forming substrate in the blood and heart of normal and diseased patients. Studies to-date document that angiotensin II generation from angiotensin-(1-12) does not require renin participation while chymase rather than angiotensin converting enzyme shows high catalytic activity in converting this tissue substrate into angiotensin II directly.
Topics: Adrenal Glands; Angiotensin I; Angiotensin II; Angiotensinogen; Animals; Biocatalysis; Bone Marrow; Brain; Cardiovascular Diseases; Chymases; Gene Expression; Humans; Intestines; Kidney; Myocardium; Peptide Fragments; Rats; Renin-Angiotensin System
PubMed: 33309638
DOI: 10.1016/j.mce.2020.111119 -
American Journal of Cardiovascular... Oct 2016Historically, the first described effect of an angiotensin converting enzyme (ACE) inhibitor was an increased activity of bradykinin, one of the substrates of ACE.... (Review)
Review
Historically, the first described effect of an angiotensin converting enzyme (ACE) inhibitor was an increased activity of bradykinin, one of the substrates of ACE. However, in the subsequent years, molecular models describing the mechanism of action of ACE inhibitors in decreasing blood pressure and cardiovascular risk have focused mostly on the renin-angiotensin system. Nonetheless, over the last 20 years, the importance of bradykinin in regulating vasodilation, natriuresis, oxidative stress, fibrinolysis, inflammation, and apoptosis has become clearer. The affinity of ACE appears to be higher for bradykinin than for angiotensin I, thereby suggesting that ACE inhibitors may be more effective inhibitors of bradykinin degradation than of angiotensin II production. Data describing the effect of ACE inhibition on bradykinin signaling support the hypothesis that the most cardioprotective benefits attributed to ACE inhibition may be due to increased bradykinin signaling rather than to decreased angiotensin II signaling, especially when high dosages of ACE inhibitors are considered. In particular, modulation of bradykinin in the endothelium appears to be a major target of ACE inhibition. These new mechanistic concepts may lead to further development of strategies enhancing the bradykinin signaling.
Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Bradykinin; Cardiovascular Diseases; Endothelium, Vascular; Humans; Renin-Angiotensin System; Risk Factors; Vasodilation
PubMed: 27260014
DOI: 10.1007/s40256-016-0173-4 -
Toxicon : Official Journal of the... Jun 2017Animal venoms are multifaceted mixtures, including proteins, peptides and enzymes produced by animals in defense, predation and digestion. These molecules have been... (Review)
Review
Animal venoms are multifaceted mixtures, including proteins, peptides and enzymes produced by animals in defense, predation and digestion. These molecules have been investigated concerning their molecular mechanisms associated and possible pharmacological applications. Thalassophryne nattereri is a small venomous fish inhabiting the northern and northeastern coast of Brazil, and represents a relatively frequent cause of injuries. Its venom causes severe inflammatory response followed frequently by the necrosis of the affected area. Scorpaena plumieri is the most venomous fish in the Brazilian fauna and is responsible for relatively frequent accidents involving anglers and bathers. In humans, its venom causes edema, erythema, ecchymoses, nausea, vomiting, and syncope. Recently, the presence of a type of angiotensin converting enzyme (ACE) activity in the venom of Thalassophryne nattereri and Scorpaena plumieri, endemic fishes in northeastern coast of Brazil, has been described. The ACE converts angiotensin I (Ang I) into angiotensin II (Ang II) and inactivates bradykinin, there by regulating blood pressure and electrolyte homeostasis, however, their function in these venoms remains an unknown. This article provides an overview of the current knowledge on ACE in the venoms of Thalassophryne nattereri and Scorpaena plumier.
Topics: Angiotensin I; Angiotensin II; Animals; Batrachoidiformes; Blood Pressure; Bradykinin; Brazil; Fish Venoms; Homeostasis; Peptidyl-Dipeptidase A
PubMed: 28284848
DOI: 10.1016/j.toxicon.2017.03.003 -
Frontiers in Immunology 2022Aneurysmal subarachnoid hemorrhage (SAH) is a substantial cause of mortality and morbidity worldwide. Moreover, survivors after the initial bleeding are often subject to... (Review)
Review
Aneurysmal subarachnoid hemorrhage (SAH) is a substantial cause of mortality and morbidity worldwide. Moreover, survivors after the initial bleeding are often subject to secondary brain injuries and delayed cerebral ischemia, further increasing the risk of a poor outcome. In recent years, the renin-angiotensin system (RAS) has been proposed as a target pathway for therapeutic interventions after brain injury. The RAS is a complex system of biochemical reactions critical for several systemic functions, namely, inflammation, vascular tone, endothelial activation, water balance, fibrosis, and apoptosis. The RAS system is classically divided into a pro-inflammatory axis, mediated by angiotensin (Ang)-II and its specific receptor ATR, and a counterbalancing system, presented in humans as Ang-(1-7) and its receptor, MasR. Experimental data suggest that upregulation of the Ang-(1-7)/MasR axis might be neuroprotective in numerous pathological conditions, namely, ischemic stroke, cognitive disorders, Parkinson's disease, and depression. In the presence of SAH, Ang-(1-7)/MasR neuroprotective and modulating properties could help reduce brain damage by acting on neuroinflammation, and through direct vascular and anti-thrombotic effects. Here we review the role of RAS in brain ischemia, with specific focus on SAH and the therapeutic potential of Ang-(1-7).
Topics: Angiotensin I; Angiotensin II; Brain Ischemia; Humans; Peptide Fragments; Subarachnoid Hemorrhage
PubMed: 35355989
DOI: 10.3389/fimmu.2022.841692 -
Molecular Pharmacology Jan 2021Bone marrow-derived hematopoietic stem/progenitor cells are vasculogenic and play an important role in endothelial health and vascular homeostasis by participating in... (Review)
Review
Bone marrow-derived hematopoietic stem/progenitor cells are vasculogenic and play an important role in endothelial health and vascular homeostasis by participating in postnatal vasculogenesis. Progenitor cells are mobilized from bone marrow niches in response to remote ischemic injury and migrate to the areas of damage and stimulate revascularization largely by paracrine activation of angiogenic functions in the peri-ischemic vasculature. This innate vasoprotective mechanism is impaired in certain chronic clinical conditions, which leads to the development of cardiovascular complications. Members of the renin-angiotensin system-angiotensin-converting enzymes (ACEs) ACE and ACE2, angiotensin II (Ang II), Ang-(1-7), and receptors AT1 and Mas-are expressed in vasculogenic progenitor cells derived from humans and rodents. Ang-(1-7), generated by ACE2, is known to produce cardiovascular protective effects by acting on Mas receptor and is considered as a counter-regulatory mechanism to the detrimental effects of Ang II. Evidence has now been accumulating in support of the activation of the ACE2/Ang-(1-7)/Mas receptor pathway by pharmacologic or molecular maneuvers, which stimulates mobilization of progenitor cells from bone marrow, migration to areas of vascular damage, and revascularization of ischemic areas in pathologic conditions. This minireview summarizes recent studies that have enhanced our understanding of the physiology and pharmacology of vasoprotective axis in bone marrow-derived progenitor cells in health and disease. SIGNIFICANCE STATEMENT: Hematopoietic stem progenitor cells (HSPCs) stimulate revascularization of ischemic areas. However, the reparative potential is diminished in certain chronic clinical conditions, leading to the development of cardiovascular diseases. ACE2 and Mas receptor are key members of the alternative axis of the renin-angiotensin system and are expressed in HSPCs. Accumulating evidence points to activation of ACE2 or Mas receptor as a promising approach for restoring the reparative potential, thereby preventing the development of ischemic vascular diseases.
Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Cardiovascular Agents; Cardiovascular Diseases; Drug Delivery Systems; Hematopoietic Stem Cells; Humans; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Receptors, G-Protein-Coupled; Signal Transduction; Stem Cells
PubMed: 32321734
DOI: 10.1124/mol.119.117580 -
American Journal of Physiology. Heart... May 2019Thirty years ago, a novel axis of the renin-angiotensin system (RAS) was unveiled by the discovery of angiotensin-(1-7) [ANG-(1-7)] generation in vivo. Later,... (Review)
Review
Thirty years ago, a novel axis of the renin-angiotensin system (RAS) was unveiled by the discovery of angiotensin-(1-7) [ANG-(1-7)] generation in vivo. Later, angiotensin-converting enzyme 2 (ACE2) was shown to be the main mediator of this reaction, and Mas was found to be the receptor for the heptapeptide. The functional analysis of this novel axis of the RAS that followed its discovery revealed numerous protective actions in particular for cardiovascular diseases. In parallel, similar protective actions were also described for one of the two receptors of ANG II, the ANG II type 2 receptor (ATR), in contrast to the other, the ANG II type 1 receptor (ATR), which mediates deleterious actions of this peptide, e.g., in the setting of cardiovascular disease. Very recently, another branch of the RAS was discovered, based on angiotensin peptides in which the amino-terminal aspartate was replaced by alanine, the alatensins. Ala-ANG-(1-7) or alamandine was shown to interact with Mas-related G protein-coupled receptor D, and the first functional data indicated that this peptide also exerts protective effects in the cardiovascular system. This review summarizes the presentations given at the International Union of Physiological Sciences Congress in Rio de Janeiro, Brazil, in 2017, during the symposium entitled "The Renin-Angiotensin System: Going Beyond the Classical Paradigms," in which the signaling and physiological actions of ANG-(1-7), ACE2, ATR, and alatensins were reported (with a focus on noncentral nervous system-related tissues) and the therapeutic opportunities based on these findings were discussed.
Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Cardiovascular Agents; Cardiovascular Diseases; Cardiovascular System; Congresses as Topic; Humans; Oligopeptides; Peptide Fragments; Peptidyl-Dipeptidase A; Receptor, Angiotensin, Type 2; Receptors, G-Protein-Coupled; Renin-Angiotensin System; Signal Transduction
PubMed: 30707614
DOI: 10.1152/ajpheart.00723.2018 -
Journal of Cellular Physiology Jan 2021The effects of the renin-angiotensin system (RAS) on stem cells isolated from human dental apical papilla (SCAPs) are completely unknown. Therefore, the aim of this...
The effects of the renin-angiotensin system (RAS) on stem cells isolated from human dental apical papilla (SCAPs) are completely unknown. Therefore, the aim of this study was to identify RAS components expressed in SCAPs and the effects of angiotensin (Ang) II and Ang-(1-7) on cell proliferation. SCAPs were collected from third molar teeth of adolescents and maintained in cell culture. Messenger RNA expression and protein levels of angiotensin-converting enzyme (ACE), ACE2, and Mas, Ang II type I (AT1) and type II (AT2) receptors were detected in SCAPs. Treatment with either Ang II or Ang-(1-7) increased the proliferation of SCAPs. These effects were inhibited by PD123319, an AT2 antagonist. While Ang II augmented mTOR phosphorylation, Ang-(1-7) induced ERK1/2 phosphorylation. In conclusion, SCAPs produce the main RAS components and both Ang II and Ang-(1-7) treatments induced cell proliferation mediated by AT2 activation through different intracellular mechanisms.
Topics: Adolescent; Angiotensin I; Angiotensin II; Cell Proliferation; Cells, Cultured; Dental Papilla; Female; Humans; Imidazoles; MAP Kinase Signaling System; Male; Peptide Fragments; Peptidyl-Dipeptidase A; Phosphorylation; Pyridines; RNA, Messenger; Receptor, Angiotensin, Type 1; Renin-Angiotensin System; Stem Cells
PubMed: 32519379
DOI: 10.1002/jcp.29862